poj-2676sudoku

思路：深搜， 主要是判斷是否在同一行，同一列，同一格。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn=10;
const int INF=0x3f3f3f3f;
int T, cnt;
int mp[maxn][maxn], row[maxn][maxn], col[maxn][maxn], grid[maxn][maxn];
int zero[maxn*maxn][2];

int location(int i, int j)
{
	return ((i-1)/3)*3+(j-1)/3+1;
}

int dfs(int step)
{
	if(step==cnt+1)
	return 1;
	for(int i=1; i<=9; i++)
	{
		if(!row[zero[step][0]][i] && !col[zero[step][1]][i] && !grid[location(zero[step][0], zero[step][1])][i])
		{
			row[zero[step][0]][i]=1;
			col[zero[step][1]][i]=1;
			grid[location(zero[step][0], zero[step][1])][i]=1;
			mp[zero[step][0]][zero[step][1]]=i;
			if(dfs(step+1))
			return 1;
			row[zero[step][0]][i]=0;
			col[zero[step][1]][i]=0;
			grid[location(zero[step][0], zero[step][1])][i]=0;
		}
	}
	return 0;
		
}

int main(){
	cin>>T;
	while(T--)
	{
		cnt=0;
		memset(col, 0, sizeof(col));
		memset(row, 0, sizeof(row));
		memset(grid, 0, sizeof(grid));
		for(int i=1; i<=9; i++)
		{
			for(int j=1; j<=9; j++)
			{
				scanf("%1d", &mp[i][j]);
				if(mp[i][j])
				{
					row[i][mp[i][j]]=1;
					col[j][mp[i][j]]=1;
					grid[location(i, j)][mp[i][j]]=1;
				}
				else
				{
					zero[++cnt][0]=i;
					zero[cnt][1]=j;			
				}	
			}
		}
		dfs(1);
		for(int i=1; i<=9; i++)
		{
			for(int j=1; j<=9; j++)
			cout<<mp[i][j];
			cout<<endl;
		}
	}
	return 0;
}