1232 畅通工程.cpp

来自「威士忌的HDU题解.大概有260多题的源码。对于学习非常有好处。」· C++ 代码 · 共 63 行

/*
1232 畅通工程
Time Limit : 2000 ms  Memory Limit : 32768 K  Output Limit : 256 K

GUN C++
*/
#include <iostream>
#include <cstdio>
#include <string>
#include <queue>
using namespace std;

const int Max=1001;
short road[Max][Max];
bool v[Max];
queue <short> Q;

int bfs(int node)
{
    short  temp,i;
    
    v[node]=true;
    temp=road[node][0];
    for(i=1;i<=temp;i++)
        if(!v[ road[node][i] ])
            Q.push(road[node][i]);
    while(!Q.empty())
    {
        temp=Q.front();
        Q.pop();
        if(!v[temp])
            bfs(temp);
    }
}

int main()
{
    int t,n,i,m,x,y,ans;

    while(scanf("%d %d",&n,&m)==2 && n!=0)
    {
        memset(v,false,sizeof(v));
        for(i=0;i<Max;i++)
            road[i][0]=0;
        for(i=0;i<m;i++)
        {
            scanf("%d %d",&x,&y);
            road[x][0]++;
            road[x][ road[x][0] ] =y;
            road[y][0]++;
            road[y][ road[y][0] ] =x;
        }
        Q.push(1);
        ans=0;
        for(i=1;i<=n;i++)
            if(!v[i])
            {   ans++;bfs(i);}
        printf("%d\n",ans-1);
    }
    return 0;
}