LeetCode 37 Sudoku Solver (C,C++,Java,Python)

Problem:

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.

Solution:

采用笨拙的DFS的办法，判断填入的数字是否合法，可以通过三个规则事先过滤掉不合法的数字，然后试试剩余的是否有合法的数字

题目大意：

填数独游戏。。。。。。

Java源代码（300ms）：

public class Solution {
public void solveSudoku(char[][] board) {
SudoKu(board,0,0);
}
private boolean SudoKu(char[][] board,int i,int j){
if(i==8 && j==9)return true;
if(j==9){
i++;j=0;
}
if(board[i][j]!='.'){
if(SudoKu(board,i,j+1))return true;
}else{
int[] map=getValidNum(board,i,j);
for(int k=1;k<10;k++){
if(map[k]==0){
board[i][j]=(char)(k+'0');
if(SudoKu(board,i,j+1))return true;
board[i][j]='.';
}
}
}
return false;
}
private int[] getValidNum(char[][] board,int i,int j){
int[] map=new int[10];
for(int k=0;k<9;k++){
if(board[i][k]!='.')map[board[i][k]-'0']=1;
if(board[k][j]!='.')map[board[k][j]-'0']=1;
}
for(int k=3*(i/3);k<3*(i/3)+3;k++){
for(int l=3*(j/3);l<3*(j/3)+3;l++){
if(board[k][l]!='.')map[board[k][l]-'0']=1;
}
}
return map;
}
}

C语言源代码（12ms）：

int* getValidNum(char** board,int i,int j){
int k,l;
int* map = (int*)malloc(sizeof(int)*10);
memset(map,0,sizeof(int)*10);
for(k=0;k<9;k++){
if(board[i][k]!='.') map[board[i][k]-'0']=1;
}
for(k=0;k<9;k++){
if(board[k][j]!='.') map[board[k][j]-'0']=1;
}
for(k=3*(i/3);k<3*(i/3)+3;k++){
for(l=3*(j/3);l<3*(j/3)+3;l++){
if(board[k][l]!='.') map[board[k][l]-'0']=1;
}
}
return map;
}
bool SudoKu(char** board,int i,int j){
int k;
if(i==8 && j==9)return true;
if(j==9){
i++;
j=0;
}
if(board[i][j]!='.'){
if(SudoKu(board,i,j+1))return true;
}else{
int* map=getValidNum(board,i,j);
for(k=1;k<10;k++){
if(map[k]==0){
board[i][j]=k+'0';
if(SudoKu(board,i,j+1))return true;
board[i][j]='.';
}
}
free(map);
}
return false;
}
void solveSudoku(char** board, int boardRowSize, int boardColSize) {
SudoKu(board,0,0);
}

C++源代码（24ms）：

class Solution {
public:
void solveSudoku(vector<vector<char>>& board) {
SudoKu(board,0,0);
}
private:
bool SudoKu(vector<vector<char>>& board,int i,int j){
if(i==8 && j==9)return true;
if(j==9){
i++;j=0;
}
if(board[i][j]!='.'){
if(SudoKu(board,i,j+1))return true;
}else{
int* map=getValidNum(board,i,j);
for(int k=1;k<10;k++){
if(map[k]==0){
board[i][j]=k+'0';
if(SudoKu(board,i,j+1))return true;
board[i][j]='.';
}
}
}
return false;
}
int* getValidNum(vector<vector<char>>& board,int i,int j){
int* map=(int*)malloc(sizeof(int)*10);
memset(map,0,sizeof(int)*10);
for(int k=0;k<9;k++){
if(board[i][k]!='.')map[board[i][k]-'0']=1;
if(board[k][j]!='.')map[board[k][j]-'0']=1;
}
for(int k=3*(i/3);k<3*(i/3)+3;k++){
for(int l=3*(j/3);l<3*(j/3)+3;l++){
if(board[k][l]!='.')map[board[k][l]-'0']=1;
}
}
return map;
}
};

Python源代码（636ms）：

class Solution:
# @param {character[][]} board
# @return {void} Do not return anything, modify board in-place instead.
def solveSudoku(self, board):
self.SudoKu(board,0,0)
def SudoKu(self,board,i,j):
if i==8 and j==9:return True
if j==9:i+=1;j=0
if board[i][j]!='.':
if self.SudoKu(board,i,j+1):return True
else:
map=self.getValidNum(board,i,j)
for k in range(1,10):
if map[k]==0:
board[i][j]=chr(k+ord('0'))
if self.SudoKu(board,i,j+1):return True
board[i][j]='.'
return False
def getValidNum(self,board,i,j):
map=[0 for k in range(10)]
for k in range(9):
if board[i][k]!='.':map[ord(board[i][k])-ord('0')]=1
if board[k][j]!='.':map[ord(board[k][j])-ord('0')]=1
for k in range(3*(i/3),3*(i/3)+3):
for l in range(3*(j/3),3*(j/3)+3):
if board[k][l]!='.':map[ord(board[k][l])-ord('0')]=1
return map