poj1703

简单并查集

#include <iostream>
#include <cstdio>
#include <cstdlib>
#include <cstring>
using namespace std;

#define maxn 100005

int n, m;
int f[maxn], father[maxn];

int getanc(int a)
{
    if (a == father[a])
        return a;
    return father[a] = getanc(father[a]);
}

void merge(int a, int b)
{
    father[getanc(a)] = getanc(b);
}

void differ(int a, int b)
{
    if (f[a] == -1)
        f[a] = b;
    else
        merge(f[a], b);
    if (f[b] == -1)
        f[b] = a;
    else
        merge(f[b], a);
}

void ask(int a, int b)
{
    if (f[a] == -1 || f[b] == -1)
    {
        printf("Not sure yet.\n");
        return;
    }
    if (getanc(a) == getanc(b))
    {
        printf("In the same gang.\n");
        return;
    }
    if (getanc(a) == getanc(f[b]))
    {
        printf("In different gangs.\n");
        return;
    }
    printf("Not sure yet.\n");
}

int main()
{
    //freopen("t.txt", "r", stdin);
    int t;
    scanf("%d", &t);
    while (t--)
    {
        memset(f, -1, sizeof(f));
        scanf("%d%d", &n, &m);
        getchar();
        for (int i = 0; i < n; i++)
            father[i] = i;
        for (int i = 0; i < m; i++)
        {
            char ch;
            int a, b;
            scanf("%c%d%d", &ch, &a, &b);
            a--;
            b--;
            getchar();
            if (ch == 'D')
                differ(a, b);
            else
                ask(a, b);
        }
    }
    return 0;
}