HDU1642 UVA167 UVALive5227 The Sultan's Successors题解

#include<iostream>
#include<cstdio>
#include<cstring>
using namespace std;
//八皇后+回溯
int ans;
int C[8];
int boards[8][8],vis[3][2*8];
void search(int cur)//问题只要求八个   cur行i列
{
if(cur==8)
{
int s=0;
for(int i=0;i<8;i++)
s+=boards[i][C[i]];
if(ans<s) ans=s;
}///走到这，所有皇后不冲突
else for(int i=0;i<8;i++)
{
if(!vis[0][i]&&!vis[1][cur+i]&&!vis[2][cur-i+8])//判断
{
C[cur]=i;
vis[0][i]=vis[1][cur+i]=vis[2][cur-i+8]=1;
search(cur+1);
vis[0][i]=vis[1][cur+i]=vis[2][cur-i+8]=0;
}
}
}
int main()
{
int k;
scanf("%d",&k);
while(k--)
{
ans=0;
memset(boards,0,sizeof(boards));
memset(vis,0,sizeof(vis));
for(int i=0;i<8;i++)
for(int j=0;j<8;j++)
scanf("%d",&boards[i][j]);
search(0);
printf("%5d\n",ans);//注意
}
return 0;
}