L2-013. 红色警报（并查集）*

L2-013. 红色警报

参考博客

 #include <cstdio>
 #include <algorithm>
 #include <iostream>
 #include <cmath>
 #include <cstring>
 using namespace std;
 int n,m;
 struct node
 {
     int u,v;
 } e[];
 int vist[],fa[];
 int Find(int x)
 {
     return x==fa[x]?fa[x]:Find(fa[x]);
 }
 void Union(int x,int y)
 {
     int xc=Find(x);
     int yc=Find(y);
     if(xc!=yc)
     {
         fa[xc]=yc;
     }
 }
 int main()
 {
     int k;
     int u,v;
     while(scanf("%d%d",&n,&m)!=EOF)
     {
         for(int i=; i<n; i++)
             fa[i]=i;
         for(int i=; i<m; i++)
         {
             scanf("%d%d",&u,&v);
             e[i].u=u,e[i].v=v;
             Union(u,v);
         }
         int num=,num1;
         for(int i=; i<n; i++)
         {
             if(fa[i]==i)
             {
                 num++;
             }
         }
         memset(vist,,sizeof(vist));
         scanf("%d",&k);
         while(k--)
         {
             num1=;
             for(int i=;i<n;i++)
                 fa[i]=i;
             int x;
             scanf("%d",&x);
             vist[x]=;
             for(int i=;i<m;i++)
             {
                 if(vist[e[i].u]==||vist[e[i].v]==)
                 continue;
                 else
                     Union(e[i].u,e[i].v);
             }
             for(int i=;i<n;i++)
                 if(fa[i]==i)
                 num1++;
             if(num==num1||num+==num1)
             printf("City %d is lost.\n",x);
             else
                 printf("Red Alert: City %d is lost!\n",x);
             num=num1;
         }
         num=;
         for(int i=;i<n;i++)
             if(vist[i]==)
             num++;
         if(num==n)
             printf("Game Over.\n");
     }
     return ;
 }