hihiocoder 1255（搜索）(2015ACM/ICPC北京站)

题意：

给你四个矩形，判断能否从中选出3个组成一个矩形

思路：

1.搜索，如果两个能组成一个新的，则将他们合并，继续搜索

2.暴力判断

最开始没注意到3，一直以为要用4个，WR

#include <cstdio>
#include <cstring>
#include <cstdlib>
using namespace std;
const int maxn = 10005;
const int INF = 0x3f3f3f3f;
int x[5];
int y[5];
int vis[5];
int ans ;
void judge(int tx,int ty)
{
    int num = 0;
    if(ans == 1)
        return;
    for(int i = 0; i < 4; i++)
    {
        if(vis[i])
            num ++;
    }
    if(num == 3)
    {
        ans = 1;
        return ;
    }
    for(int i = 0; i < 4; i++)
    {
        if(!vis[i])
        {
            vis[i] = 1;
            if(tx == x[i])
                judge(tx,ty+y[i]);
            else if(tx == y[i])
                judge(tx,ty+x[i]);
            else if(ty == y[i])
                judge(tx + x[i],ty);
            else if(ty == x[i])
                judge(tx + y[i],ty);
            vis[i] = 0;
        }
    }
    return ;
}

int main()
{
    int T;
    scanf("%d",&T);
    while(T--)
    {
        ans = 0;
        memset(vis,0,sizeof(vis));
        for(int i = 0; i < 4; i ++)
        {
            scanf("%d%d",&x[i],&y[i]);
        }
        for(int i = 0; i < 4; i++)
        {
            vis[i] = 1;
            judge(x[i],y[i]);
            vis[i] = 0;
            if(ans == 1)
                break;
        }
        if(ans == 1)
            printf("Yes
");
        else
            printf("No
");
    }
    return 0;
}