HDU-1213(简单DFS)

这道题目是一道简单的DFS,只需要用邻接表构出边之后,进行DFS,

一次DFS之后自加1,就可以

贴出代码:

#include <stdio.h>#include <string.h>#include <stdlib.h>#include <math.h>int N,M;//N represents the number of points,and M stands for the number of edges;int head[2000];struct Edge{int v;int next;}e[2000];int visit[2000];int idx;void addedge(int a,int b){idx++;e[idx].v=b;e[idx].next=head[a];head[a]=idx;}void DFS(int x){visit[x]=1;for(int p=head[x];p!=-1;p=e[p].next){int v=e[p].v;if(!visit[v]){DFS(v);}}}int main(){int T;scanf("%d",&T);while(T--){int a,b;int cn=0;idx=0;memset(visit,0,sizeof(visit));memset(head,-1,sizeof(head));scanf("%d%d",&N,&M);for(int i=1;i<=M;i++){scanf("%d%d",&a,&b);addedge(a,b);addedge(b,a);}for(i=1;i<=N;i++){if(!visit[i]){DFS(i);cn++;}}printf("%d\n",cn);}return 0;}