题解 | 划分子集

详细解析可见https://mp.weixin.qq.com/s/Jhazg56d_7umBdRR-k0_rA

#include <iostream>
using namespace std;

const int N = 10010;

int p[N], num[N];

int find(int x) {
    if(p[x] != x) p[x] = find(p[x]);
    return p[x];
}

void union1(int a, int b) {
    int fa = find(a), fb = find(b);
    if(fa != fb) p[fa] = fb; 
}

int main() {
    int n, m;
    cin >> n >> m;
    for(int i = 1; i <= n; i++) {
        p[i] = i;
        num[i] = 0;
    }
    for(int i = 0; i < m; i++) {
        int a, b;
        cin >> a >> b;
        union1(a, b);
    }
    int res = 0;
    for(int i = 1; i <= n; i++) num[find(i)]++;
    for(int i = 1; i <= n; i++) {
        if(num[i] > res) res = num[i];
    }
    
    cout << res;
    return 0;
}