POJ 2492 A Bug's Life

这题跟 POJ 1703 Find them and Catch them 是一样一样的，就不讲解了，不懂可以看

http://www.cnblogs.com/whatbeg/p/3498416.html

 

代码：

#include <iostream>

#include <cstdio>

using namespace std;

#define N 2100



int fa[N],sa[N];



void makeset(int n)

{

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

    {

        fa[i] = i;

        sa[i] = 0;  // 0 : same   1 : different

    }

}



int findset(int x)

{

    if(x != fa[x])

    {

        int tmp = fa[x];

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

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

    }

    return fa[x];

}



void unionset(int a,int b)

{

    int x = findset(a);

    int y = findset(b);

    if(x == y)

        return;

    fa[x] = y;

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

    return;

}



int main()

{

    int t,n,m,i;

    int a,b;

    int cs = 1;

    scanf("%d",&t);

    while(t--)

    {

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

        makeset(n);

        int flag = 1;

        for(i=1;i<=m;i++)

        {

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

            if(findset(a) == findset(b))

            {

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

                {

                    flag = 0;

                }

            }

            else

                unionset(a,b);

        }

        printf("Scenario #%d:\n",cs++);

        if(flag)

            cout<<"No suspicious bugs found!"<<endl;

        else

            cout<<"Suspicious bugs found!"<<endl;

        cout<<endl;

    }

    return 0;

}

View Code