poj 2492 A Bug's Life

并查集的高级应用.

#include <cstdio>using namespace std;#define max_n 2300int father[max_n];int relation[max_n];int n,m;void init(){for(int i=1;i<=n;i++){father[i] = i;relation[i] = 0;}}int find(int x){if(x!=father[x])father[x] = find(father[x]);return father[x];}void get_in(int a,int b){int x = find(a);int y = find(b);if(x!=y)father[y] = x;}int main(){int t;int i;scanf("%d",&t);for(i=1;i<=t;i++){bool flag = false;int a,b;scanf("%d%d",&n,&m);init();while(m--){scanf("%d%d",&a,&b);if(flag)continue;if(find(a)==find(b)){flag = true;}if(relation[a]==0&&relation[b]==0){relation[a] = b;relation[b] = a;}else if(relation[a]==0){relation[a] = b;get_in(a,relation[b]);}else if(relation[b]==0){relation[b] = a;get_in(b,relation[a]);}else{get_in(a,relation[b]);get_in(b,relation[a]);}}printf("Scenario #%d:\n",i);if(flag){printf("Suspicious bugs found!\n\n");}else{printf("No suspicious bugs found!\n\n");}}}