poj - 2492 种类并查集

题意：有t组测试数据, 对于每组数据,第一行n, m分别表示昆虫的数目和接下来m行x, y,x, y表示教授判断x, y为异性, 问教授是否有错误判断,即存在x, y为同性;

种类并查集 0 表示同性， 1表示异性

链接：poj 2492

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <cmath>
#include <cstdlib>
#include <limits>
#include <vector>
#include <sstream>
#define ll long long

using namespace std;

const int maxn = 2000 + 10;
const int maxm = 1000000 + 10;
const int inf = 0x3f3f3f3f;

int father[maxn];
int r[maxn];

int n, m, k;

void init() {
    for(int i = 0; i <= n; i++) {
        father[i] = i;
        r[i] = 0;
    }
}

int getf(int x) {
    int t;
    if(father[x] != x) {
        t = getf(father[x]);
        r[x] = (r[x] + r[father[x]]) % 2;
        return father[x] = t;
    }
    return x;
}

int main()
{
    int kcase = 0;
    int T;
    scanf("%d", &T);
    while(T--) {
        scanf("%d %d", &n, &m);
        init();
        int flag = 1;
        while(m--) {
            int a, b;
            scanf("%d %d", &a, &b);
            int x = getf(a), y = getf(b);
            if(x == y) {
                if((r[a] + r[b]) % 2 == 0) {
                    flag = 0;
                }
            }
            else {
                father[x] = y;
                r[x] = (r[a] + r[b] + 1) % 2;
            }
        }
        if(kcase) puts("");
        printf("Scenario #%d:\n", ++kcase);
        if(flag) puts("No suspicious bugs found!");
        else puts("Suspicious bugs found!");
    }
    return 0;
}