萌新求助0分

闰土，参考第一篇题解的写法，结果爆零w(ﾟДﾟ)w（

在线求助dalao

#include <iostream>
#include <cstdio>
const int N = 400005; 
using namespace std;
int k, n, m, head[N], cnt, broke[N], ans[N];
int fa[N];
bool Broken[N];
struct Node {
    int next, num, from;
} h[400002];
void Add(int x, int y) {
    h[++cnt].from = x;
    h[cnt].next = head[x];
    head[x] = cnt;
    h[cnt].num = y;
}
int Get(int x) {
    if(fa[x] == x) return x;
    return fa[x] = Get(fa[x]);
}
void merge(int x, int y) {
    x = Get(x), y = Get(y);
    if(x != y) fa[y] = x;
}
int main() {
    ios::sync_with_stdio(false);
    cin >> n >> m;
    for(int i = 0; i <= n; i++) fa[i] = i, head[i] = -1;
    for(int i = 1; i <= m; i++) {
        int x, y;
        scanf("%d%d", &x, &y);
        Add(x, y);
        Add(y, x);
    }
    cin >> k;
    for(int i = 1; i <= k; i++) {
        scanf("%d", &broke[i]);
        Broken[broke[i]] = true;
    }
    int sum = n - k;
    for(int i = 1; i <= 2 * m; i++) {
        if(!Broken[h[i].from] && !Broken[h[i].num] && Get(h[i].from) != Get(h[i].num)) {
            sum--;
            merge(h[i].from, h[i].num);
        }
    }
    ans[k + 1] = sum;
    for(int i = k; i >= 1; i--) {
        sum++;
        Broken[broke[i]] = false;
        for(int j = head[broke[i]]; j != -1; j = h[j].next) {
            if(!Broken[h[j].num] && Get(broke[i]) != Get(h[j].num)) {
                sum--;
                merge(broke[i], h[j].num);
            }
        }
        ans[i] = sum;
    }
    for(int i = 1; i <= k + 1; i++) {
        printf("%d\n", ans[i]);
    }
    return 0;
}