POJ 2676 Sudoku （DFS）

#include<iostream>
#include<algorithm>
#include<cstring>
#include<string>
#include<sstream>
#include<queue>
#include<cstdio>
using namespace std;
typedef long long LL;
const int INF = 0x3f3f3f3f;
const int M = 1010;

int vish[15][15];
int visl[15][15];
int vis[15][15];
char s[15][15];
int mp[15][15];
int flag;

int dfs(int x, int y, int sum)
{
if (flag)
return 1;

if (sum == 0)
{
for (int i = 0; i < 9; ++i)
{
for (int j = 0; j < 9; ++j)
{
cout << mp[i][j];
}
puts("");
}

flag = 1;
return 1;
}

while (mp[x][y] != 0)
{
if (y == 8 && x == 8)
break;
if (y == 8)
{
x++;
y = 0;
}
else
y++;
}
for (int i = 1; i <= 9; ++i)
{
if (!vish[x][i] && !visl[y][i] && !vis[(y / 3) + (x / 3) * 3 + 1][i])
{
vish[x][i] = 1;
visl[y][i] = 1;
vis[(y / 3) + (x / 3) * 3 + 1][i] = 1;
mp[x][y] = i;
sum--;
dfs(x, y, sum);
sum++;
vish[x][i] = 0;
visl[y][i] = 0;
mp[x][y] = 0;
vis[(y / 3) + (x / 3) * 3 + 1][i] = 0;

}

}

return 0;
}

int main()
{
int t;
scanf("%d", &t);
while (t--)
{
memset(visl, 0, sizeof(visl));
memset(vish, 0, sizeof(vish));
memset(vis, 0, sizeof(vis));

for (int i = 0; i < 9; ++i)
{
for (int j = 0; j < 9; ++j)
{
cin >> s[i][j];
mp[i][j] = s[i][j] - '0';
}
}
int ans = 0;
for (int i = 0; i < 9; ++i)
{
for (int j = 0; j < 9; ++j)
{
//cout << ( j/ 3) + (i / 3) * 3 +1<< " ";
int tmp = mp[i][j];
if (tmp == 0)
{
ans++;
continue;
}

vish[i][tmp] = 1;
visl[j][tmp] = 1;
vis[(j / 3) + (i / 3) * 3 + 1][tmp] = 1;
}
//puts("");
}
//cout << ans << endl;
flag = 0;
dfs(0, 0, ans);

}

return 0;

}