class Solution(object):
def solveSudoku(self, board):
"""
:type board: List[List[str]]
:rtype: void Do not return anything, modify board in-place instead.
"""
self.m = len(board)
self.n = len(board[0])
self.visit = [[False for i in range(self.n)] for i in range(self.m)]
# wrong
self.direction = [[-1,0],[0,1],[1,0],[0,-1]]
self.count = 0
self.startX = None
self.startY = None
for x in range(self.m):
for y in range(self.n):
if board[x][y] == ".":
self.count += 1
if not self.startX and not self.startY :
self.startX = x
self.startY = y
self.putNumber(board,self.startX,self.startY)
def inArea(self,x,y):
return x >= 0 and x < self.m and y >= 0 and y < self.n
def putNumber(self,board,x,y):
self.visit[x][y] = True
for i in range(1,10):
if self.validRow(board,x,i) and self.validCol(board,y,i) and self.validSquare(board,x,y,i):
board[x][y] = str(i)
self.count -= 1
if self.count == 0:
print board
for item in self.direction:
newX = x + item[0]
newY = y + item[1]
if self.inArea(newX,newY) and not self.visit[newX][newY] and board[newX][newY] == ".":
self.putNumber(board,newX,newY)
board[x][y] = "."
self.count -= 1
self.visit[x][y] = False
return
def validRow(self,board,x,num):
for i in range(self.n):
if board[x][i] == str(num):
return False
return True
def validCol(self,board,y,num):
for i in range(self.m):
if board[i][y] == str(num):
return False
return True
def validSquare(self,board,x,y,num):
xIndex = x / 3
yIndex = y /3
sX = xIndex * 3
sY = yIndex * 3
for i in range(3):
for j in range(3):
if board[sX+i][sY+j] == str(num):
return False
else:
return True
class Solution2(object):
def solveSudoku(self, board):
"""
:type board: List[List[str]]
:rtype: void Do not return anything, modify board in-place instead.
"""
self.m = len(board) self.n = len(board[0]) self.res = [] self.count = 0 pointSet = [] for x in range(self.m): for y in range(self.n): if board[x][y] == ".": pointSet.append([x,y]) self.putNumber(board,pointSet,0) def inArea(self,x,y): return x >= 0 and x < self.m and y >= 0 and y < self.n def putNumber(self,board,pointSet,index): if index == len(pointSet): for i in range(self.m): self.res.append(board[i][0:]) return True x = pointSet[index][0] y = pointSet[index][1] for i in range(1,10): if self.validRow(board,x,i) and self.validCol(board,y,i) and self.validSquare(board,x,y,i): board[x][y] = str(i) if self.putNumber(board,pointSet,index+1): return board[x][y] = "." return def validRow(self,board,x,num): for i in range(self.n): if board[x][i] == str(num): return False return True def validCol(self,board,y,num): for i in range(self.m): if board[i][y] == str(num): return False return True def validSquare(self,board,x,y,num): xIndex = x / 3 yIndex = y /3 sX = xIndex * 3 sY = yIndex * 3 for i in range(3): for j in range(3): if board[sX+i][sY+j] == str(num): return False else: return Trues = Solution2()# board1 = [# ["5","3","."],# ["6",".","."],# [".","9","8"]# ]board2 = [["5","3",".",".","7",".",".",".","."],["6",".",".","1","9","5",".",".","."],[".","9","8",".",".",".",".","6","."],["8",".",".",".","6",".",".",".","3"],["4",".",".","8",".","3",".",".","1"],["7",".",".",".","2",".",".",".","6"],[".","6",".",".",".",".","2","8","."],[".",".",".","4","1","9",".",".","5"],[".",".",".",".","8",".",".","7","9"]]s.solveSudoku(board2)print s.res