PAT甲级真题1166

思路：判断是否为团，是的话看能否加入一个顶点

代码：

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;
const int N = 300;
bool st[N];
int g[N][N];

int main()
{
    
    int n,m;
    scanf("%d%d", &n, &m);
    while (m -- ){
    
        int x,y;
        scanf("%d%d", &x, &y);
        g[x][y] = g[y][x] = true;
    }
    
    scanf("%d", &m);
    
    for(int t = 1; t <= m; t++){
    
        int cnt ;
        memset(st, 0, sizeof st);
        
        scanf("%d", &cnt);
        while(cnt-- ){
    
            int x;
            scanf("%d", &x);
            st[x] = true;
        }
        
        bool is_clique = true;
        
        for(int i = 1; i <= n; i++)
            for(int j = i + 1; j <= n; j++)
                if(st[i]&&st[j]&&!g[i][j])
                    is_clique = false;
        if(!is_clique){
    
            printf("Area %d needs help.\n",t);
        }else{
    
            int id = 0;
            
            for(int i = 1; i <= n; i++){
    
                if(!st[i]){
    
                    bool is_join = true;
                    for(int j = 1; j <= n; j++)
                        if(st[j]&&!g[i][j]){
    
                            is_join = false;
                            break;
                        }
                        
                    if(is_join){
    
                        id = i;
                        break;
                    }
                    
                }
            }
            
            if(id) printf("Area %d may invite more people, such as %d.\n", t, id);
            else printf("Area %d is OK.\n", t);
        }
    }
    
}