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48 lines
1001 B

#include<bits/stdc++.h>
// https://blog.csdn.net/qq_41923622/article/details/79756107
using namespace std;
int a[10][10];
int bj[3][20]= {0};
int bj1[3][20]= {0};
int n;
int sum=0;
void f2(int x ) {
int y;
if(x==n)sum++;
else {
for(y=0; y<n; y++)
if(a[x][y]==1&&bj1[0][y]==0&&bj1[1][x+y]==0&&bj1[2][x-y+n]==0) {
a[x][y]=3;
bj1[0][y]=bj1[1][x+y]=bj1[2][x-y+n]=1;
f2(x+1);
bj1[0][y]=bj1[1][x+y]=bj1[2][x-y+n]=0;
a[x][y]=1;
}
}
}
void f(int x ) { //放置白后
int y;
if(x==n)f2(0);//放置 黑后
else {
for(y=0; y<n; y++)
if(a[x][y]==1&&bj[0][y]==0&&bj[1][x+y]==0&&bj[2][x-y+n]==0) { //左右对角 列 和当前坐标都未被标记可放
a[x][y]=2;//标记白后 放置位置 为防放置黑后 放重
bj[0][y]=bj[1][x+y]=bj[2][x-y+n]=1;//标记左右对角 列
f(x+1);
bj[0][y]=bj[1][x+y]=bj[2][x-y+n]=0;//清除标记
a[x][y]=1;
}
}
}
int main() {
int i,j;
scanf("%d",&n);
for(i=0; i<n; i++)
for(j=0; j<n; j++)
scanf("%d",&a[i][j]);
f(0);
printf("%ld\n",sum);
return 0;
}