HDU ACM 1232 畅通工程(并查集)

http://acm.hdu.edu.cn/showproblem.php?pid=1232

题意:不好说,自己看.

基本上根据并查集模版写出代码,只是作出简单的调用和在函数Union()中增加了道路数量的计算.

#include <iostream>
using namespace std;
const int MAX = 1000 + 100;
int father[MAX];
int rank1[MAX];
int sign[MAX];
int step;
void Make_Set(int x)//初始化
{
    father[x] = x;
    rank1[x] = 0;
}

int Find_Set(int x)//找根节点
{
    int i=0;
    while(father[x] != x)
    {
        sign[i++] = x;
        x = father[x];
    }
    for(i;i>=1;i--)
    {
        father[sign[i-1]] = x;
    }
    return x;
}


void Union(int x,int y)//合并
{
    x = Find_Set(x);
    y = Find_Set(y);
    if(x == y)
    {
        return;
    }
    step ++;//计算步数
    if(rank1[x] > rank1[y])
    {
        father[y] = x;
    }
    else if(rank1[x] < rank1[y])
    {
        father[x] = y;
    }
    else if(rank1[x] ==rank1[y]) 
    {
        father[x] = y;           
        rank1[y]++;             
    }
}

int main()
{
    int n,m;
    while(cin>>n,n)
    {
        cin>>m;
        step =0;
        int i;
        for(i=1;i<=n;i++)
        {
            Make_Set(i);
        }
        for(i=1;i<=m;i++)
        {
            int a,b;
            cin>>a>>b;
            Union(a,b);
        }
        cout<<n-step-1<<endl;
    }
    return 0;
}