并查集 带压缩路径的版本

#include <iostream>

using namespace std;

 

typedef struct

{

    int a,b;

}road;

 

const int MAX=5001;

int N,M,K;

int father[MAX];

int rank[MAX];

road rd[500000];

 

void make_set()

{

    int i;

    for(i=1;i<=N;i++)

    {

        father[i]=i;

        rank[i]=0;

    }

}

 

int find_set(int x)

{

    if(x!=father[x])

        father[x]=find_set(father[x]);

    return father[x];

}

 

void union_set(int x,int y)

{

    x=find_set(x);

    y=find_set(y);

    if(x==y)

        return ;

    if(rank[x]>rank[y])

        father[y]=x;

    else

    {

        father[x]=y;

        if(rank[x]==rank[y])

            rank[y]++;

    }

}

 

int main()

{

    cin>>N>>M>>K;

    int i,j;

    int start,end;

    int input;

    for(i=1;i<=M;i++)

    {

        cin>>start>>end;

        rd[i].a=start;

        rd[i].b=end;

    }

    for(i=1;i<=K;i++)

    {

        int cnt=-2;

        cin>>input;

        make_set();

        for(j=1;j<=M;j++)

        {

            if(rd[j].a!=input && rd[j].b!=input)

                union_set(rd[j].a,rd[j].b);

        }

        for(j=1;j<=N;j++)

        {

            if(father[j]==j)

                cnt++;

        }

        cout<<cnt<<endl;

    }

    return 0;

}

/**************************************************************

    Problem: 1325

    User: feng345feng

    Language: C++

    Result: Accepted

    Time:800 ms

    Memory:5456 kb

****************************************************************/