update README

README.md

@@ -0,0 +1,16 @@
+# Sudoku in Löve
+
+## Shortcuts
+
+- l: go right
+- k: go up
+- j: go down
+- h: go left
+- tab: toggle editing bit / small numbers
+- s: show search space
+- a: insert certain numbers
+- u: undo
+- f: save current state to "lastBoard.txt"
+- c: solve the puzzle
+- -: zoom out
+- =: zoom in

boards/040.txt

@@ -7,3 +7,13 @@
 7 0 0 0 0 0 0 3 0
 0 0 1 2 3 0 8 6 0
 0 0 0 0 0 0 2 0 1
+
+2 3 4 7 6 5 1 9 8
+1 8 7 9 4 2 6 5 3
+9 5 6 3 8 1 7 2 4
+4 7 8 5 2 3 9 1 6
+6 2 5 1 9 8 3 4 7
+3 1 9 4 7 6 5 8 2
+7 6 2 8 1 9 4 3 5
+5 4 1 2 3 7 8 6 9
+8 9 3 6 5 4 2 7 1

boards/041.txt

@@ -0,0 +1,9 @@
+0 0 4 3 0 0 2 0 9
+0 0 5 0 0 9 0 0 1
+0 7 0 0 6 0 0 4 3
+0 0 6 0 0 2 0 8 7
+1 9 0 0 0 7 4 0 0
+0 5 0 0 8 3 0 0 0
+6 0 0 0 0 0 1 0 5
+0 0 3 5 0 8 6 9 0
+0 4 2 9 1 0 3 0 0

boards/042.txt

@@ -0,0 +1,19 @@
+9 2 6 0 0 0 0 0 1
+0 5 0 0 0 0 0 2 0
+0 0 0 4 9 0 0 0 7
+0 6 0 0 4 0 0 1 0
+2 0 0 0 0 7 0 0 0
+0 4 5 0 3 0 7 0 0
+0 0 0 0 0 4 0 0 9
+0 9 3 0 0 0 5 0 0
+0 0 0 0 0 0 8 0 6
+
+9 2 6 3 7 5 4 8 1
+7 5 4 1 6 8 9 2 3
+8 3 1 4 9 2 6 5 7
+3 6 7 8 4 9 2 1 5
+2 8 9 5 1 7 3 6 4
+1 4 5 2 3 6 7 9 8
+5 7 8 6 2 4 1 3 9
+6 9 3 7 8 1 5 4 2
+4 1 2 9 5 3 8 7 6

boards/043.txt

@@ -0,0 +1,19 @@
+0 0 0 0 7 0 0 0 6
+0 6 0 4 0 9 0 8 7
+0 1 0 8 0 0 0 0 9
+0 0 0 0 0 0 4 0 0
+0 0 0 1 0 4 6 0 0
+0 0 4 0 5 0 0 0 0
+3 8 0 5 0 0 0 0 0
+0 0 0 0 0 2 0 7 0
+9 0 6 0 0 0 5 0 2
+
+4 9 8 2 7 1 3 5 6
+2 6 5 4 3 9 1 8 7
+7 1 3 8 6 5 2 4 9
+6 5 9 7 8 3 4 2 1
+8 3 7 1 2 4 6 9 5
+1 2 4 9 5 6 7 3 8
+3 8 2 5 1 7 9 6 4
+5 4 1 6 9 2 8 7 3
+9 7 6 3 4 8 5 1 2

boards/044.txt

@@ -0,0 +1,19 @@
+5 8 4 0 2 3 0 7 0
+0 0 0 8 0 0 0 0 4
+0 0 0 0 0 4 0 0 8
+3 0 6 7 0 0 0 4 0
+4 0 0 0 3 0 0 0 9
+0 1 0 0 0 9 3 0 5
+2 0 0 5 0 0 0 0 0
+6 0 0 0 0 2 0 0 0
+0 4 0 9 7 0 6 2 3
+
+5 8 4 1 2 3 9 7 6
+1 6 3 8 9 7 2 5 4
+9 2 7 6 5 4 1 3 8
+3 9 6 7 1 5 8 4 2
+4 5 8 2 3 6 7 1 9
+7 1 2 4 8 9 3 6 5
+2 3 1 5 6 8 4 9 7
+6 7 9 3 4 2 5 8 1
+8 4 5 9 7 1 6 2 3

boards/045.txt

@@ -0,0 +1,19 @@
+0 6 0 0 0 0 9 5 8
+0 0 0 0 0 0 0 0 7
+0 0 0 3 0 0 2 0 0
+0 0 0 0 0 5 3 0 0
+7 0 0 0 0 6 0 0 0
+8 0 4 0 1 0 6 0 0
+1 0 0 0 0 0 0 0 3
+5 9 0 0 7 0 0 0 6
+0 2 0 0 0 0 4 0 0
+
+3 6 2 1 4 7 9 5 8
+4 8 5 6 9 2 1 3 7
+9 7 1 3 5 8 2 6 4
+2 1 6 7 8 5 3 4 9
+7 3 9 4 2 6 5 8 1
+8 5 4 9 1 3 6 7 2
+1 4 8 5 6 9 7 2 3
+5 9 3 2 7 4 8 1 6
+6 2 7 8 3 1 4 9 5

boards/046.txt

@@ -0,0 +1,19 @@
+8 9 0 0 0 2 0 4 0
+5 0 0 0 0 0 0 0 3
+0 0 0 0 0 1 0 5 0
+0 0 5 6 0 0 0 9 0
+0 0 2 0 0 0 5 0 0
+0 4 0 0 0 0 0 0 8
+0 0 1 0 4 0 2 0 9
+7 0 0 8 0 0 0 0 6
+0 0 0 3 0 0 0 0 0
+
+8 9 7 5 3 2 6 4 1
+5 1 6 4 7 8 9 2 3
+2 3 4 9 6 1 8 5 7
+1 7 5 6 8 4 3 9 2
+6 8 2 1 9 3 5 7 4
+9 4 3 2 5 7 1 6 8
+3 5 1 7 4 6 2 8 9
+7 2 9 8 1 5 4 3 6
+4 6 8 3 2 9 7 1 5

boards/047.txt

@@ -0,0 +1,19 @@
+0 0 0 0 0 1 8 0 7
+4 0 0 0 0 5 0 2 0
+0 0 0 0 2 0 0 5 9
+0 3 0 0 0 0 2 1 4
+1 0 0 4 3 7 0 0 6
+6 4 5 0 0 0 0 8 0
+5 2 0 0 6 0 0 0 0
+0 1 0 7 0 0 0 0 2
+7 0 6 2 0 0 0 0 0
+
+2 5 3 6 9 1 8 4 7
+4 6 9 8 7 5 3 2 1
+8 7 1 3 2 4 6 5 9
+9 3 7 5 8 6 2 1 4
+1 8 2 4 3 7 5 9 6
+6 4 5 9 1 2 7 8 3
+5 2 4 1 6 3 9 7 8
+3 1 8 7 5 9 4 6 2
+7 9 6 2 4 8 1 3 5

boards/048.txt

@@ -0,0 +1,19 @@
+8 0 0 6 1 0 0 0 0
+0 2 7 0 0 0 4 0 6
+0 1 6 0 7 0 8 0 0
+0 3 0 0 6 5 2 0 0
+0 0 0 0 9 0 0 0 0
+0 0 4 8 2 0 0 5 0
+0 0 1 0 8 0 6 4 0
+4 0 9 0 0 0 7 8 0
+0 0 0 0 4 6 0 0 9
+
+8 4 3 6 1 2 9 7 5
+9 2 7 5 3 8 4 1 6
+5 1 6 4 7 9 8 2 3
+1 3 8 7 6 5 2 9 4
+2 7 5 3 9 4 1 6 8
+6 9 4 8 2 1 3 5 7
+3 5 1 9 8 7 6 4 2
+4 6 9 2 5 3 7 8 1
+7 8 2 1 4 6 5 3 9

boards/049.txt

@@ -0,0 +1,19 @@
+0 1 0 6 0 0 0 7 3
+9 0 0 0 0 0 0 0 4
+0 4 0 2 0 0 0 0 0
+0 7 0 0 0 8 4 0 0
+0 0 4 0 0 0 6 0 0
+3 0 0 0 0 0 0 1 0
+7 0 6 0 1 0 2 0 0
+8 0 0 0 0 3 0 0 5
+0 0 0 0 0 9 0 0 0
+
+2 1 8 6 9 4 5 7 3
+9 6 7 3 5 1 8 2 4
+5 4 3 2 8 7 1 9 6
+6 7 9 1 3 8 4 5 2
+1 5 4 9 7 2 6 3 8
+3 8 2 5 4 6 9 1 7
+7 3 6 8 1 5 2 4 9
+8 9 1 4 2 3 7 6 5
+4 2 5 7 6 9 3 8 1

boards/050.txt

@@ -0,0 +1,19 @@
+0 4 0 0 7 2 1 0 8
+0 0 0 3 0 6 5 4 0
+0 0 0 0 0 4 0 0 3
+0 0 0 0 8 0 0 5 6
+0 0 7 0 9 0 4 0 0
+4 8 0 0 2 0 0 0 0
+7 0 0 5 0 0 0 0 0
+0 6 4 2 0 9 0 0 0
+8 0 5 7 6 0 0 2 0
+
+5 4 3 9 7 2 1 6 8
+9 7 8 3 1 6 5 4 2
+6 2 1 8 5 4 7 9 3
+3 1 9 4 8 7 2 5 6
+2 5 7 6 9 3 4 8 1
+4 8 6 1 2 5 9 3 7
+7 3 2 5 4 8 6 1 9
+1 6 4 2 3 9 8 7 5
+8 9 5 7 6 1 3 2 4

boards/051.txt

@@ -0,0 +1,19 @@
+3 4 0 0 0 0 7 6 0
+2 0 0 0 0 0 0 0 0
+5 0 1 7 0 6 0 0 8
+0 0 0 2 6 0 0 0 0
+0 0 0 0 0 9 0 4 0
+0 0 7 0 0 0 0 0 0
+0 0 0 0 0 8 0 0 0
+6 0 0 0 0 0 0 5 1
+0 0 0 0 4 3 9 2 0
+
+3 4 8 5 9 1 7 6 2
+2 7 6 8 3 4 1 9 5
+5 9 1 7 2 6 4 3 8
+4 1 3 2 6 7 5 8 9
+8 5 2 3 1 9 6 4 7
+9 6 7 4 8 5 2 1 3
+1 2 9 6 5 8 3 7 4
+6 3 4 9 7 2 8 5 1
+7 8 5 1 4 3 9 2 6

boards/052.txt

@@ -0,0 +1,19 @@
+0 6 0 0 0 0 5 9 3
+0 0 0 0 0 0 0 0 4
+0 0 0 7 0 0 2 0 0
+0 0 0 0 0 9 7 0 0
+4 0 0 0 0 6 0 0 0
+3 0 8 0 1 0 6 0 0
+1 0 0 0 0 0 0 0 7
+9 5 0 0 4 0 0 0 6
+0 2 0 0 0 0 8 0 0
+
+7 6 2 1 8 4 5 9 3
+8 3 9 6 5 2 1 7 4
+5 4 1 7 9 3 2 6 8
+2 1 6 4 3 9 7 8 5
+4 7 5 8 2 6 9 3 1
+3 9 8 5 1 7 6 4 2
+1 8 3 9 6 5 4 2 7
+9 5 7 2 4 8 3 1 6
+6 2 4 3 7 1 8 5 9

boards/053.txt

@@ -0,0 +1,19 @@
+0 0 0 0 5 8 0 0 4
+8 0 7 0 0 0 1 3 0
+0 0 4 0 1 0 8 5 0
+0 0 3 2 8 0 0 9 0
+0 0 0 0 6 0 0 0 0
+0 2 0 0 3 4 7 0 0
+0 7 8 0 4 0 5 0 0
+0 4 1 0 0 0 6 0 7
+6 0 0 8 7 0 0 0 0
+
+2 1 6 3 5 8 9 7 4
+8 5 7 4 9 2 1 3 6
+9 3 4 6 1 7 8 5 2
+7 6 3 2 8 1 4 9 5
+4 8 5 7 6 9 2 1 3
+1 2 9 5 3 4 7 6 8
+3 7 8 1 4 6 5 2 9
+5 4 1 9 2 3 6 8 7
+6 9 2 8 7 5 3 4 1

boards/054.txt

@@ -0,0 +1,19 @@
+0 3 6 0 7 8 0 0 1
+7 0 0 5 0 0 0 0 4
+0 0 0 0 0 3 0 0 7
+9 0 1 0 0 2 0 4 0
+2 0 0 0 8 0 0 0 6
+0 6 0 9 0 0 7 0 8
+3 0 0 8 0 0 0 0 0
+6 0 0 0 0 7 0 0 2
+8 0 0 1 9 0 4 7 0
+
+4 3 6 2 7 8 9 5 1
+7 2 8 5 1 9 6 3 4
+1 9 5 6 4 3 2 8 7
+9 8 1 7 6 2 3 4 5
+2 7 3 4 8 5 1 9 6
+5 6 4 9 3 1 7 2 8
+3 1 7 8 2 4 5 6 9
+6 4 9 3 5 7 8 1 2
+8 5 2 1 9 6 4 7 3

boards/055.txt

@@ -0,0 +1,19 @@
+0 8 0 0 0 2 4 5 0
+9 0 3 4 0 0 0 0 0
+0 0 0 0 3 0 1 0 0
+1 0 6 0 0 0 0 0 0
+0 0 0 0 0 0 9 0 0
+0 0 0 5 0 0 0 2 8
+0 0 0 3 1 0 6 0 0
+4 0 0 0 0 9 0 0 0
+2 3 0 0 0 0 0 7 0
+
+6 8 7 1 9 2 4 5 3
+9 1 3 4 7 5 2 8 6
+5 4 2 8 3 6 1 9 7
+1 2 6 9 8 7 5 3 4
+8 7 5 2 4 3 9 6 1
+3 9 4 5 6 1 7 2 8
+7 5 9 3 1 8 6 4 2
+4 6 8 7 2 9 3 1 5
+2 3 1 6 5 4 8 7 9

boards/056.txt

@@ -0,0 +1,19 @@
+8 2 0 0 0 0 7 0 3
+7 0 0 5 4 0 1 0 0
+5 6 0 0 0 7 0 0 0
+0 0 3 0 0 0 0 0 0
+0 0 0 0 5 0 0 0 9
+0 0 0 4 0 1 0 0 0
+9 0 0 0 0 0 0 2 0
+0 0 7 8 2 0 3 1 0
+0 0 0 0 0 0 8 0 7
+
+8 2 4 9 1 6 7 5 3
+7 3 9 5 4 8 1 6 2
+5 6 1 2 3 7 9 8 4
+4 9 3 6 8 2 5 7 1
+1 8 6 7 5 3 2 4 9
+2 7 5 4 9 1 6 3 8
+9 1 8 3 7 5 4 2 6
+6 4 7 8 2 9 3 1 5
+3 5 2 1 6 4 8 9 7

boards/057.txt

@@ -0,0 +1,9 @@
+0 6 0 0 0 0 0 0 9
+0 0 0 0 0 3 5 8 0
+0 4 5 6 0 0 1 7 0
+0 0 0 9 0 0 0 0 1
+6 0 9 8 4 1 7 0 5
+1 0 0 0 0 2 0 0 0
+0 7 1 0 0 8 9 6 0
+0 9 6 2 0 0 0 0 0
+4 0 0 0 0 0 0 1 0

config.lua

@@ -1,6 +1,6 @@
 return {
     board = {
-        filePath = "boards/040.txt",
+        filePath = "boards/057.txt",
     },
     window = {
         bgColor = "FFFFFF",

main.lua

@@ -1,4 +1,4 @@
-require "sudoku.utils"
+sudoku = require "sudoku.sudoku"
 uiUtils = require "ui.utils"
 config = require "config"
 SudokuCanvas = require "ui.sudokucanvas"
@@ -11,10 +11,10 @@ function love.load()
     love.mouse.setGrabbed(false)
     love.keyboard.setKeyRepeat(true)
     math.randomseed(os.time())
-    local board = loadBoard(config.board.filePath)
+    board = sudoku.loadBoard(config.board.filePath)
     local width, height = love.graphics.getDimensions()
-    sudokuCanvas = SudokuCanvas:new(200, 100, height/1.5, config.SudokuCanvas)
-    sudokuCanvas:setBoard(board)
+    sudokuCanvas = SudokuCanvas:new(500, 50, height/1.1, config.SudokuCanvas)
+    sudokuCanvas:setBoard(board[1])
     myFont = love.graphics.newFont(24)
 end
 

sudoku/check.lua

@@ -1,132 +0,0 @@
-local function checkCT(ct)
-    local r = {}
-    for i = 1, 8 do
-        for j = i+1, 9 do
-            if ct[i] == ct[j] and ct[i] ~= 0 then
-                table.insert(r, {i, j})
-            end
-        end
-    end
-    if #r > 0 then return false, r end
-    return true
-end
-
-local function findThisTable(this, that)
-    for i = 1, #that do
-        if #that[i] == #this then
-            local flag = true
-            for j = 1, #this do
-                if this[j] ~= that[i][j] then flag = false; break end
-            end
-            if flag then return true, i end
-        end
-    end
-    return false
-end
-
-function check(board)
-    local rr = {}
-    for x = 1, 9 do
-        local ct = {}
-        for y = 1, 9 do
-            ct[y] = board[x][y]
-        end
-        local ok, r = checkCT(ct)
-        if not ok then
-            for _, p in ipairs(r) do
-                local t = {x, p[1], x, p[2], board[x][p[1]]}
-                if not findThisTable(t, rr) then
-                    table.insert(rr, t)
-                end
-            end
-        end
-    end
-    for y = 1, 9 do
-        local ct = {}
-        for x = 1, 9 do
-            ct[x] = board[x][y]
-        end
-        local ok, r = checkCT(ct)
-        if not ok then
-            for _, p in ipairs(r) do
-                local t = {p[1], y, p[2], y, board[p[1]][y]}
-                if not findThisTable(t, rr) then
-                    table.insert(rr, t)
-                end
-            end
-        end
-    end
-    for i = 0, 2 do
-        for j = 0, 2 do
-            local ct = {}
-            for x = 1, 3 do
-                for y = 1, 3 do
-                    ct[(x-1)*3+y] = board[x+i*3][y+j*3]
-                end
-            end
-            local ok, r = checkCT(ct)
-            if not ok then
-                for _, p in ipairs(r) do
-                    -- local x1 = ((p[1] - 1) // 3 + 1) + i * 3
-                    local x1 = math.floor((p[1] - 1) / 3 + 1) + i * 3
-                    local y1 = ((p[1] - 1) % 3 + 1) + j * 3
-                    -- local x2 = ((p[2] - 1) // 3 + 1) + i * 3
-                    local x2 = math.floor((p[2] - 1) / 3 + 1) + i * 3
-                    local y2 = ((p[2] - 1) % 3 + 1) + j * 3
-                    local t = {x1, y1, x2, y2, board[x1][y1]}
-                    if not findThisTable(t, rr) then
-                        table.insert(rr, t)
-                    end
-                end
-            end
-        end
-    end
-    if #rr > 0 then
-        return false, rr
-    end
-    return true
-end
-
-function checkSolved(board)
-    local r = {}
-    for i = 1, 9 do
-        for j = 1, 9 do
-            if board[i][j] < 1 or board[i][j] > 9 then
-                table.insert(r, {i, j, board[i][j]})
-            end
-        end
-    end
-    local ok, rr = check(board)
-    if #r > 0 or (rr and #rr > 0) then
-        return false, r, rr
-    end
-    return true
-end
-
-function pcheck(board)
-    local ok, r, rr = checkSolved(board)
-    if ok then
-        print("Board is solved!")
-        return 
-    end
-    for _, p in ipairs(r) do
-        print(S("(%d, %d) = %d", unpack(p)))
-    end
-    for _, p in ipairs(rr) do
-        print(S("(%d, %d) = (%d, %d) = %d", unpack(p)))
-    end
-end
-
-function scheck(board)
-    local msg = {}
-    local ok, r = check(board)
-    if ok then
-        return {"No Error!"}
-    end
-    for _, p in ipairs(r) do
-        local s = string.format("(%d, %d) = (%d, %d) = %d", unpack(p))
-        print(s)
-        table.insert(msg, s)
-    end
-    return msg
-end

sudoku/sudoku.lua

@@ -1,47 +1,510 @@
-require "sudoku.utils"
-require "sudoku.check"
+-- dbg = require ("debugger")
+-- dbg.auto_where = 2
 
-function calValidOptions(b, x, y)
-    if b[x][y] ~= 0 then return {} end
-    local elm
-    local u = {}
-    local v = {}
-    for i = 1, 9 do
-        elm = b[x][i]
-        if elm ~= 0 and find(u, elm) == 0 then
-            table.insert(u, elm)
-        end
-        elm = b[i][y]
-        if elm ~= 0 and find(u, elm) == 0 then
-            table.insert(u, elm)
+function table2string(t)
+    local myself = table2string
+    local l = {}
+    local n = 0
+    for k, v in pairs(t) do
+        n = n + 1
+        if type(v) == "table" then
+            l[n] = k .. ': ' .. myself(v)
+        elseif type(v) == "string" then
+            l[n] = k .. ': ' .. '"' .. v .. '"'
+        else
+            l[n] = k .. ': ' .. v
         end
     end
-    -- local xc = ((x - 1) // 3) * 3
-    -- local yc = ((y - 1) // 3) * 3
-    local xc = math.floor((x - 1) / 3) * 3
-    local yc = math.floor((y - 1) / 3) * 3
-    for i = 1, 3 do
-        for j = 1, 3 do
-            elm = b[i+xc][j+yc]
-            if elm ~= 0 and find(u, elm) == 0 then
-                table.insert(u, elm)
+    return "{" .. table.concat(l, ", ") .. "}"
+end
+
+function find(array, element)
+    local index = 0
+    for i = 1, #array do
+        if array[i] == element then
+            index = i
+            break
+        end
+    end
+    return index
+end
+
+function createEmptyBoard()
+    local b = {}
+    for i = 1, 9 do
+        b[i] = {}
+        for j = 1, 9 do
+            b[i][j] = 0
+        end
+    end
+    return b
+end
+
+function cloneBoard(b)
+    local c = {}
+    for i = 1, 9 do
+        c[i] = {}
+        for j = 1, 9 do
+            c[i][j] = b[i][j]
+        end
+    end
+    return c
+end
+
+function loadBoard(fn)
+    local boards = {}
+    local r = 0
+    local board = {}
+    for line in io.lines(fn) do
+        if line:gsub("%s+", "") == "" then
+            table.insert(boards, board)
+            board = {}
+            r = 0
+        else
+            r = r + 1
+            local c = 0
+            board[r] = {}
+            for item in line:gmatch("%w+") do
+                c = c + 1
+                board[r][c] = tonumber(item)
             end
         end
     end
+    table.insert(boards, board)
+    return boards
+end
+
+function saveBoard(fn, b1, b2)
+    local f = io.open(fn, "w")
+    for row = 1, 9 do
+        f:write(table.concat(b1[row], " "))
+        f:write("\n")
+    end
+    f:write("\n")
+    for row = 1, 9 do
+        f:write(table.concat(b2[row], " "))
+        f:write("\n")
+    end
+    f:close()
+end
+
+function showBoard(board)
+    for row = 1, 9 do
+        print(table.concat(board[row], " "))
+    end
+end
+
+function checkBoardsEqual(b1, b2)
     for i = 1, 9 do
-        if find(u, i) == 0 then table.insert(v, i) end
+        for j = 1, 9 do
+            if b1[i][j] ~= b2[i][j] then return false end
+        end
+    end
+    return true
+end
+
+function iterZones(board)
+    local row = 0
+    local column = 0
+    local block = 0
+    return function()
+        local a = {}
+        local p = {}
+        if row < 9 then
+            row = row + 1
+            for i = 1, 9 do
+                a[i] = board[row][i]
+                p[i] = {row, i}
+            end
+            return a, p
+        end
+        if column < 9 then
+            column = column + 1
+            for i = 1, 9 do
+                a[i] = board[i][column]
+                p[i] = {i, column}
+            end
+            return a, p
+        end
+        if block < 9 then
+            block = block + 1
+            local dx = math.floor((block - 1) / 3)
+            local dy = (block - 1) % 3
+            local n = 0
+            for i = 1, 3 do
+                for j = 1, 3 do
+                    local x = i + 3 * dx
+                    local y = j + 3 * dy
+                    n = n + 1
+                    a[n] = board[x][y]
+                    p[n] = {x, y}
+                end
+            end
+            return a, p
+        end
+    end
+end
+
+function checkAUX(zone, pos)
+    local isComplete = true
+    local ok = true
+    local conflictList = {}
+    local n = 0
+    for i = 1, 8 do
+        for j = i+1, 9 do
+            if zone[i] == 0 then
+                isComplete = false
+            elseif zone[i] == zone[j] then
+                ok = false
+                n = n + 1
+                conflictList[n] = {x1=pos[i][1], y1=pos[i][2], x2=pos[j][1], y2=pos[j][2]}
+            end
+        end
+    end
+    return ok, isComplete, conflictList
+end
+
+function checkBoard(board)
+    local ok = true
+    local isComplete = true
+    local conflictList = {}
+    for zone, pos in iterZones(board) do
+        local tOk, tIsComplete, tConflictList = checkAUX(zone, pos)
+        if not tOk then ok = false end
+        if not tIsComplete then isComplete = false end
+        for _, conflict in ipairs(tConflictList) do
+            table.insert(conflictList, conflict)
+        end
+    end
+    if not ok then isComplete = false end
+    return ok, isComplete, conflictList
+end
+
+function calCellValidOptions(board, x, y)
+    if board[x][y] ~= 0 then return {} end
+    local u = {}
+    local v = {}
+    for i = 1, 9 do
+        if board[x][i] ~= 0 then table.insert(u, board[x][i]) end
+        if board[i][y] ~= 0 then table.insert(u, board[i][y]) end
+    end
+    local dx = math.floor((x - 1) / 3) * 3
+    local dy = math.floor((y - 1) / 3) * 3
+    for i = 1, 3 do
+        for j = 1, 3 do
+            local a = board[i+dx][j+dy]
+            if a ~= 0 then table.insert(u, a) end
+        end
+    end
+    for i = 1, 9 do
+        local found = false
+        for _, elm in ipairs(u) do
+            if elm == i then found = true; break end
+        end
+        if not found then table.insert(v, i) end
     end
     return v
 end
 
-function buildSearchSpace(b)
+function buildSearchSpace(board)
     local s = {}
     for i = 1, 9 do
         s[i] = {}
         for j = 1, 9 do
-            s[i][j] = calValidOptions(b, i, j)
+            s[i][j] = calCellValidOptions(board, i, j)
         end
     end
     return s
 end
 
+function findPairsIndSearchSpace(board, searchSpace)
+    local r = {}
+    local zoneIndex = 0
+    for zone, pos in iterZones(board) do
+        zoneIndex = zoneIndex + 1
+        for i = 1, 8 do
+            local x1 = pos[i][1]
+            local y1 = pos[i][2]
+            local s1 = searchSpace[x1][y1]
+            if #s1 == 2 then
+                for j = i + 1, 9 do
+                    local x2 = pos[j][1]
+                    local y2 = pos[j][2]
+                    local s2 = searchSpace[x2][y2]
+                    if #s2 == 2 then
+                        if s1[1] == s2[1] and s1[2] == s2[2] then
+                            -- if zoneIndex <= 18 or x1 ~= x2 and y1 ~= y2 then
+                            table.insert(r, {zoneIndex=zoneIndex, cells={i, j}, pair=s1})
+                                -- print("----------")
+                                -- print("zone: ", zoneIndex)
+                                -- print(table2string(zone))
+                                -- print(i, j)
+                                -- print(table2string(s1))
+                            -- end
+                        end
+                    end
+                end
+            end
+        end
+    end
+    return r
+end
+
+function showSearchSpace(s)
+    local hl = ("+-------+-------+-------+-------+-------+-------+-------+-------+-------+")
+    print(hl)
+    for i = 1, 27 do
+        local x = math.floor((i - 1) / 3) + 1
+        local a = (i - 1) % 3
+        local row = {}
+        for j = 1, 27 do
+            local y = math.floor((j - 1) / 3) + 1
+            local k = ((j - 1) % 3 + 1) + 3 * a
+            local found = false
+            for _, m in ipairs(s[x][y]) do
+                if m == k then found = true; break end
+            end
+            if found then
+                table.insert(row, k)
+            else
+                table.insert(row, " ")
+            end
+            if j % 3 == 0 then table.insert(row, "|") end
+        end
+        print("| "..table.concat(row, " "))
+        if i % 3 == 0 then print(hl) end
+    end
+end
+
+function getZoneByIndex(board, zoneIndex)
+    local index = (zoneIndex - 1) % 9 + 1
+    local block = math.floor((zoneIndex - 1) / 9) + 1
+    local a = {}
+    local p = {}
+    if block == 1 then
+        for i = 1, 9 do
+            a[i] = board[index][i]
+            p[i] = {index, i}
+        end
+    elseif block == 2 then
+        for i = 1, 9 do
+            a[i] = board[i][index]
+            p[i] = {index, i}
+        end
+    elseif block == 3 then
+        local dx = math.floor((index - 1) / 3)
+        local dy = (index - 1) % 3
+        local n = 0
+        for i = 1, 3 do
+            for j = 1, 3 do
+                local x = i + 3 * dx
+                local y = j + 3 * dy
+                n = n + 1
+                a[n] = board[x][y]
+                p[n] = {x, y}
+            end
+        end
+    end
+    return a, p
+end
+
+function getZonePosByIndex(zoneIndex)
+    local index = (zoneIndex - 1) % 9 + 1
+    local block = math.floor((zoneIndex - 1) / 9) + 1
+    local p = {}
+    if block == 1 then
+        for i = 1, 9 do
+            p[i] = {index, i}
+        end
+    elseif block == 2 then
+        for i = 1, 9 do
+            p[i] = {index, i}
+        end
+    elseif block == 3 then
+        local dx = math.floor((index - 1) / 3)
+        local dy = (index - 1) % 3
+        local n = 0
+        for i = 1, 3 do
+            for j = 1, 3 do
+                local x = i + 3 * dx
+                local y = j + 3 * dy
+                n = n + 1
+                p[n] = {x, y}
+            end
+        end
+    end
+    return p
+end
+
+function iterZonePos(zoneIndex)
+    local p = getZonePosByIndex(zoneIndex)
+    local i = 0
+    return function()
+        if i < 9 then
+            i = i + 1
+            return p[i][1], p[i][2]
+        end
+    end
+end
+
+function fillSingles(board, searchSpace)
+    local count = 0
+    for i = 1, 9 do
+        for j = 1, 9 do
+            if #searchSpace[i][j] == 1 then
+                board[i][j] = searchSpace[i][j][1]
+                count = count + 1
+            end
+        end
+    end
+    return count
+end
+
+function applyFillSinglesRepeatedly(board, s)
+    local s = s or buildSearchSpace(board)
+    local count = fillSingles(board, s)
+    local total = count
+    while count ~= 0 do
+        s = buildSearchSpace(board)
+        count = fillSingles(board, s)
+        total = total + count
+    end
+    return total
+end
+
+function eliminatePairsInSearchSpaceAUX(board, searchSpace, pair, zoneIndex, cells)
+    local _, pos = getZoneByIndex(board, zoneIndex)
+    local count = 0
+    for i = 1, 9 do
+        if i ~= cells[1] and i ~= cells[2] then
+            local x = pos[i][1]
+            local y = pos[i][2]
+            local del = {}
+            for index, v in ipairs(searchSpace[x][y]) do
+                if v == pair[1] or v == pair[2] then
+                    count = count + 1
+                    table.insert(del, index)
+                end
+            end
+            for _, index in ipairs(del) do
+                table.remove(searchSpace[x][y], index)
+            end
+        end
+    end
+    return count
+end
+
+function eliminatePairsInSearchSpace(board, searchSpace)
+    local p = findPairsIndSearchSpace(board, searchSpace)
+    local count = 0
+    for _, m in ipairs(p) do
+        count = count + eliminatePairsInSearchSpaceAUX(board, searchSpace, m.pair, m.zoneIndex, m.cells)
+    end
+    return count
+end
+
+function allPairs(board)
+    local s = buildSearchSpace(board)
+    applyFillSinglesRepeatedly(board, s)
+    eliminatePairsInSearchSpace(board, s)
+    local count = applyFillSinglesRepeatedly(board, s)
+    while count ~= 0 do
+        -- print("--------------------------------------------------")
+        -- showBoard(board)
+        -- showSearchSpace(s)
+        -- print(count)
+        -- io.read(1)
+        s = buildSearchSpace(board)
+        eliminatePairsInSearchSpace(board, s)
+        count = applyFillSinglesRepeatedly(board, s)
+    end
+end
+
+function findFirstEmptyCell(board)
+    for i = 1, 9 do
+        for j = 1, 9 do
+            if board[i][j] == 0 then
+                return i, j
+            end
+        end
+    end
+end
+
+function checkSearchSpace(board, searchSpace)
+    local s = searchSpace or buildSearchSpace(board)
+    for i = 1, 9 do
+        for j = 1, 9 do
+            if board[i][j] == 0 then
+                if #s[i][j] == 0 then return false end
+            end
+        end
+    end
+    return true
+end
+
+function findFirstLeastOption(searchSpace)
+    local min = 9
+    local x, y
+    for i = 1, 9 do
+        for j = 1, 9 do
+            local len = #searchSpace[i][j]
+            if len > 0 and len < min then
+                min = len
+                x = i
+                y = j
+            end
+        end
+    end
+    return x, y, min
+end
+
+function backTrace(trace)
+    while true do
+        local currentStep = trace[#trace]
+        applyFillSinglesRepeatedly(currentStep.board)
+        local ok, finished = checkBoard(currentStep.board)
+        if not ok then rollBack(trace); goto endOfTheLoop end
+        if finished then return currentStep.board end
+        local s = buildSearchSpace(currentStep.board)
+        ok = checkSearchSpace(currentStep.board, s)
+        if not ok then rollBack(trace); goto endOfTheLoop end
+        if not currentStep.pointer then
+            local x, y = findFirstLeastOption(s)
+            currentStep.options = s[x][y]
+            currentStep.pointer = 0
+            currentStep.x = x
+            currentStep.y = y
+        end
+        currentStep.pointer = currentStep.pointer + 1
+        if currentStep.pointer > #currentStep.options then rollBack(trace); goto endOfTheLoop end
+        local nextStep = {}
+        nextStep.board = cloneBoard(currentStep.board)
+        nextStep.board[currentStep.x][currentStep.y] = currentStep.options[currentStep.pointer]
+        trace[#trace+1] = nextStep
+    ::endOfTheLoop::
+    end
+end
+
+function rollBack(trace)
+    assert(#trace > 1, "Something is very wrong!")
+    table.remove(trace)
+end
+
+function solve(board)
+    local t = {}
+    t[1] = {board=cloneBoard(board),}
+    return backTrace(t)
+end
+
+return {
+    loadBoard = loadBoard,
+    cloneBoard = cloneBoard,
+    createEmptyBoard = createEmptyBoard,
+    calCellValidOptions = calCellValidOptions,
+    checkBoard = checkBoard,
+    applyFillSinglesRepeatedly = applyFillSinglesRepeatedly,
+    showBoard = showBoard,
+    checkBoardsEqual = checkBoardsEqual, 
+    saveBoard = saveBoard,
+    solve = solve,
+}

sudoku/utils.lua

@@ -1,49 +0,0 @@
-function find(array, element)
-    local index = 0
-    for i = 1, #array do
-        if array[i] == element then
-            index = i
-            break
-        end
-    end
-    return index
-end
-
-function showBoard(board)
-    for row = 1, 9 do
-        print(table.concat(board[row], " "))
-    end
-end
-
-function cloneBoard(b)
-    local c = {}
-    for i = 1, 9 do
-        c[i] = {}
-        for j = 1, 9 do
-            c[i][j] = b[i][j]
-        end
-    end
-    return c
-end
-
-function loadBoard(fn)
-    local problem = {}
-    local solution = {}
-    local board = problem
-    local r = 0
-    for line in io.lines(fn) do
-        if line:gsub("%s+", "") == "" then
-            board = solution
-            r = 0
-        else
-            r = r + 1
-            local c = 0
-            board[r] = {}
-            for item in line:gmatch("%w+") do
-                c = c + 1
-                board[r][c] = tonumber(item)
-            end
-        end
-    end
-    return problem, solution
-end

sudokuGUI

@@ -0,0 +1,3 @@
+#! /bin/sh
+
+love .

ui/sudokucanvas.lua

@@ -1,23 +1,65 @@
-function table2string(t)
-    local myself = table2string
-    local l = {}
-    local n = 0
-    for k, v in pairs(t) do
-        n = n + 1
-        if type(v) == "table" then
-            l[n] = k .. ': ' .. myself(v)
-        elseif type(v) == "string" then
-            l[n] = k .. ': ' .. '"' .. v .. '"'
-        else
-            l[n] = k .. ': ' .. v
-        end
-    end
-    return "{" .. table.concat(l, ", ") .. "}"
-end
-
 SudokuCanvas = {}
 SudokuCanvas.__index = SudokuCanvas
 
+function SudokuCanvas:pushHistory()
+    if #self.history <= 1 then
+        table.insert(self.history, sudoku.cloneBoard(self.board[2]))
+        -- showHistory(self)
+        -- print("pushHistory: ", #self.history)
+    elseif not sudoku.checkBoardsEqual(self.board[2], self.history[#self.history]) then
+        table.insert(self.history, sudoku.cloneBoard(self.board[2]))
+        -- showHistory(self)
+        -- print("pushHistory: ", #self.history)
+    end
+end
+
+function showHistory(self)
+    for i, v in ipairs(self.history) do
+        print(string.format("-- [%03d] ----------", i))
+        sudoku.showBoard(v)
+    end
+end
+
+function undo(self)
+    if #self.history > 1 then
+        showHistory(self)
+        table.remove(self.history)
+        self.board[2] = sudoku.cloneBoard(self.history[#self.history])
+        self.board[3] = sudoku.cloneBoard(self.board[2])
+
+        -- self.board[2] = sudoku.cloneBoard(self.history[#self.history])
+        -- self.history[#self.history] = nil
+
+        self:checkBoard(true)
+        print"-------------------------------------------"
+        showHistory(self)
+    end
+end
+
+function applyAllSingles(self)
+    sudoku.applyFillSinglesRepeatedly(self.board[2])
+    self.board[3] = sudoku.cloneBoard(self.board[2])
+    self:checkBoard()
+end
+
+function showValidOptionsForCurrentCell(self, x, y)
+    local s = sudoku.calCellValidOptions(self.board[2], y, x)
+    for num = 1, 9 do
+        self.smallNumbers[x][y][num].enabled = false
+    end
+    for _, num in ipairs(s) do
+        self.smallNumbers[x][y][num].enabled = true
+    end
+end
+
+function showValidOptionsForAllCells(self)
+    for x = 1, 9 do
+        for y = 1, 9 do
+            showValidOptionsForCurrentCell(self, x, y)
+        end
+    end
+end
+
 local function selectSmallNumbersFont(cellSize)
     local fntSize = 65
     local margin = 0
@@ -187,9 +229,11 @@ end
 function SudokuCanvas:setBoard(board, board2)
     local board2 = board2 or board
     self.board = {}
-    self.board[1] = cloneBoard(board)
-    self.board[2] = cloneBoard(board2)
-    self.board[3] = cloneBoard(board2)
+    self.board[1] = sudoku.cloneBoard(board)
+    self.board[2] = sudoku.cloneBoard(board2)
+    self.board[3] = sudoku.cloneBoard(board2)
+    -- self.board[4] = createEmptyBoard()
+    self:checkBoard()
 end
 
 function SudokuCanvas:new(x, y, size, options)
@@ -208,6 +252,7 @@ function SudokuCanvas:new(x, y, size, options)
         colors = options.colors,
         enabled = true,
         focused = true,
+        history = {},
     }
     o.grid = buildGrid(x, y, cellSize)
     o.smallNumbers = calSmallNumbersCoordinates(o.grid)
@@ -225,6 +270,16 @@ end
 function SudokuCanvas:focus()
 end
 
+function SudokuCanvas:checkBoard(hist)
+    if not hist then self:pushHistory() end
+    local ok, isComplete, conflictList = sudoku.checkBoard(self.board[2])
+    self.board[4] = sudoku.createEmptyBoard()
+    for _, c in ipairs(conflictList) do
+        self.board[4][c.x1][c.y1] = 1
+        self.board[4][c.x2][c.y2] = 1
+    end
+end
+
 function SudokuCanvas:draw()
     local grid = self.grid
 
@@ -270,14 +325,22 @@ function SudokuCanvas:draw()
                 local px = self.bigNumbers[x][y][num].typed.x
                 local py = self.bigNumbers[x][y][num].typed.y
                 love.graphics.setFont(self.bigNumbers.typedFont)
-                uiUtils.setColor(self.colors.bigNumbersTyped)
+                if self.board[4][y][x] ~= 0 then
+                    uiUtils.setColor(self.colors.bigNumbersError)
+                else
+                    uiUtils.setColor(self.colors.bigNumbersTyped)
+                end
                 love.graphics.print(tostring(num), px, py)
             elseif self.board[2][y][x] ~= 0 then
                 local num = self.board[2][y][x]
                 local px = self.bigNumbers[x][y][num].handWritten.x
                 local py = self.bigNumbers[x][y][num].handWritten.y
                 love.graphics.setFont(self.bigNumbers.handWrittenFont)
-                uiUtils.setColor(self.colors.bigNumbersHandWritten)
+                if self.board[4][y][x] ~= 0 then
+                    uiUtils.setColor(self.colors.bigNumbersError)
+                else
+                    uiUtils.setColor(self.colors.bigNumbersHandWritten)
+                end
                 love.graphics.print(tostring(num), px, py)
             end
         end
@@ -315,17 +378,25 @@ function SudokuCanvas:keypressed(key)
         local num = key:byte() - 48
         if self.board[1][y][x] == 0 then
             if mode == "big" then
-                self.board[2][y][x] = num
-                self.board[3][y][x] = num
+                if self.board[2][y][x] == num then
+                    self.board[2][y][x] = 0
+                    self.board[3][y][x] = 0
+                else
+                    self.board[2][y][x] = num
+                    self.board[3][y][x] = num
+                end
+                -- self:checkBoard()
             else
                 self.smallNumbers[x][y][num].enabled = not self.smallNumbers[x][y][num].enabled
             end
+            self:checkBoard()
         end
     elseif key == "delete" or key == "0" then
         if self.board[1][y][x] == 0 then
             if mode == "big" then
                 self.board[2][y][x] = 0
                 self.board[3][y][x] = 0
+                self:checkBoard()
             else
                 for num = 1, 9 do
                     self.smallNumbers[x][y][num].enabled = false
@@ -353,6 +424,18 @@ function SudokuCanvas:keypressed(key)
             self.board[2][y][x] = self.board[3][y][x]
             mode = "big"
         end
+    elseif key == "s" then
+        -- showValidOptionsForCurrentCell(self, x, y)
+        showValidOptionsForAllCells(self)
+    elseif key == "a" then
+        applyAllSingles(self)
+    elseif key == "u" then
+        undo(self)
+    elseif key == "f" then
+        sudoku.saveBoard("lastBoard.txt", self.board[1], self.board[2])
+    elseif key == "c" then
+        self.board[2] = sudoku.solve(self.board[1])
+        self:checkBoard()
     end
     self.cursor.x = x
     self.cursor.y = y