POJ 1703 Find them,Catch them ----种类并查集(经典)

http://blog.csdn.net/freezhanacmore/article/details/8774033?reload  这篇讲解非常好，我也是受这篇文章的启发才做出来的。

 

代码：

#include <iostream>

#include <cstdio>

#include <cstring>

#include <cmath>

#include <algorithm>

using namespace std;

#define N 100100



int fa[N],same[N];



void makeset(int n)

{

    for(int i=1;i<=n;i++)

    {

        fa[i] = i;

        same[i] = 0;

    }

}



int findset(int x)

{

    if(x != fa[x])

    {

        int tmp = fa[x];

        fa[x] = findset(fa[x]);

        same[x] = (same[x] + same[tmp])%2;

    }

    return fa[x];

}



int unionset(char s,int a,int b)

{

    int x = findset(a);

    int y = findset(b);

    if(x == y)    //属于同一个集合

    {

        if(s == 'A')

        {

            if(same[a] == same[b])

            {

                return 1;  //same

            }

            else

            {

                return 0;  //different

            }

        }

    }

    else  //不属于同一个集合

    {

        if(s == 'A')

        {

            return 2;    //unsure

        }

        else if(s == 'D')

        {

            fa[x] = y;

            same[x] = (same[a] + same[b] + 1)%2;

        }

    }

    return 3;  //要加，这是对其他情况的处理，因为此函数必须返回一个值

}



int main()

{

    int t,n,m,i;

    char ss[5];

    int a,b;

    scanf("%d",&t);

    while(t--)

    {

        scanf("%d%d",&n,&m);

        makeset(n);

        for(i=0;i<m;i++)

        {

            scanf("%s %d %d",ss,&a,&b);

            if(unionset(ss[0],a,b) == 1)

            {

                cout<<"In the same gang."<<endl;

            }

            else if(unionset(ss[0],a,b) == 0)

            {

                cout<<"In different gangs."<<endl;

            }

            else if(unionset(ss[0],a,b) == 2)

            {

                cout<<"Not sure yet."<<endl;

            }

        }

    }

    return 0;

}

View Code