poj 2676

Description

Sudoku is a very simple task. A square table with 9 rows and 9 columns is divided to 9 smaller squares 3x3 as shown on the Figure. In some of the cells are written decimal digits from 1 to 9. The other cells are empty. The goal is to fill the empty cells with decimal digits from 1 to 9, one digit per cell, in such way that in each row, in each column and in each marked 3x3 subsquare, all the digits from 1 to 9 to appear. Write a program to solve a given Sudoku-task. 

Input

Output

Sample Input

1
103000509
002109400
000704000
300502006
060000050
700803004
000401000
009205800
804000107

Sample Output

143628579
572139468
986754231
391542786
468917352
725863914
237481695
619275843
854396127

Source

Southeastern Europe 2005

AC代码：

#include<iostream>
using namespace std;
char G[15][15];
char ch[15]={'0','1','2','3','4','5','6','7','8','9'};
int a[15]={0,1,1,1,4,4,4,7,7,7};
int sucess;
int judge(int x,int y,int k){
	for(int i=1;i<=9;i++){
		if(G[x][i]==ch[k])
		    return 0;
	}
	for(int i=1;i<=9;i++){
		if(G[i][y]==ch[k])
		    return 0;
	}
	for(int i=a[x];i<=a[x]+2;i++)
	    for(int j=a[y];j<=a[y]+2;j++)
	        if(G[i][j]==ch[k])
	            return 0;
	return 1;
}
void dfs(int x,int y){
	if(sucess)
	    return ;
	if(x*y>81){
		for(int i=1;i<=9;i++){
		    for(int j=1;j<=9;j++)
		        cout<<G[i][j];
		    cout<<endl;
		}
		sucess=1;
		return ;
	}

	if(G[x][y]!='0'){
		if(y==9)
		    dfs(x+1,1);
		else
		    dfs(x,y+1);
	}
	else{
		for(int k=1;k<=9;k++){
			if(judge(x,y,k)){
				G[x][y]=ch[k];
				if(y==9)
		            dfs(x+1,1);
		        else
		            dfs(x,y+1);
		        G[x][y]='0';
			}
		}
	}

}
int main(){
	int T; cin>>T;
	while(T--){
		for(int i=1;i<=9;i++)
		    cin>>G[i]+1;
		sucess=0;
		dfs(1,1);
	}
	return 0;
}

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poj 2676

原文：http://blog.csdn.net/my_acm/article/details/38338767