标签：style blog http color io 使用 ar for 2014
原题地址：https://oj.leetcode.com/problems/sudoku-solver/
题意：
Write a program to solve a Sudoku puzzle by filling the empty cells.
Empty cells are indicated by the character ‘.‘.
You may assume that there will be only one unique solution.
A sudoku puzzle...
...and its solution numbers marked in red.
解题思路1：(这个版本在2014/09/12刚测试通过)
求数独的解，dancing links不会，只能写个位压缩版了。。
http://c4fun.cn/blog/2014/03/20/leetcode-solution-02/#Sudoku_Solver
class Solution: # @param board, a 9x9 2D array # Solve the Sudoku by modifying the input board in-place. # Do not return any value. def solveSudoku(self, board): lt, rt, bt = [0] * 9, [0] * 9, [0] * 9 self.dt = {} for i in range(9): self.dt[1<<i] = chr(ord(‘1‘)+i) for i in range(9): board[i] = list(board[i]) for j in range(9): if (board[i][j] == ‘.‘): continue; num = ord(board[i][j]) - ord(‘1‘) lt[i] |= 1 << num rt[j] |= 1 << num bt[j//3*3+i//3] |= 1 << num self.dfs(board, 0, lt, rt, bt) board = [‘‘.join(s) for s in board] def dfs(self, board, p, lt, rt, bt): while p < 81 and board[p/9][p%9] != ‘.‘: p += 1 if p == 81: return True i, j, k = p//9, p%9, p%9//3*3+p//9//3 if board[i][j] != ‘.‘: self.dfs(board, p + 1, lt, rt, bt) return True can = (~(lt[i]|rt[j]|bt[k])) & (0x1ff) pre = board[i] while can: num = can&-can board[i][j] = self.dt[num] lt[i] |= num rt[j] |= num bt[k] |= num if self.dfs(board, p + 1, lt, rt , bt): return True board[i][j] = ‘.‘ lt[i] &= ~num rt[j] &= ~num bt[k] &= ~num can -= num return False
解题思路2：(这个版本在2014/09/12刚测试, 超时,未通过)
使用dfs来解决问题。
http://www.cnblogs.com/zuoyuan/p/3770271.html
class Solution: # @param board, a 9x9 2D array # Solve the Sudoku by modifying the input board in-place. # Do not return any value. def solveSudoku(self, board): def isValid(x,y): tmp=board[x][y]; board[x][y]=‘D‘ for i in range(9): if board[i][y]==tmp: return False for i in range(9): if board[x][i]==tmp: return False for i in range(3): for j in range(3): if board[(x/3)*3+i][(y/3)*3+j]==tmp: return False board[x][y]=tmp return True def dfs(board): for i in range(9): for j in range(9): if board[i][j]==‘.‘: for k in ‘123456789‘: board[i][j]=k if isValid(i,j) and dfs(board): return True board[i][j]=‘.‘ return False return True dfs(board)
[leetcode]Sudoku Solver @ Python
标签：style blog http color io 使用 ar for 2014
原文地址：http://www.cnblogs.com/asrman/p/3969525.html
