[ABC229E] Graph Destruction 题解

合集 - 题解(22)

1.AT_abc333_e [ABC333E] Takahashi Quest 题解2023-12-172.[ABC265F] Manhattan Cafe 题解2023-12-243.[ABC271E] Subsequence Path 题解2024-01-034.[ABC273D] LRUD Instructions 题解2024-01-055.P8085 [COCI2011-2012#4] KRIPTOGRAM 题解2024-02-296.[ABC238F] Two Exams 题解2024-02-297.[ABC217F] Make Pair 题解2024-03-018.[ABC219F] Cleaning Robot 题解2024-03-099.[ABC219E] Moat 题解2024-03-1010.[ABC221D] Online games 题解2024-04-0411.[ABC221E] LEQ 题解2024-04-0412.[ABC223E] Placing Rectangles 题解2024-04-0413.[ABC211D] Number of Shortest paths 题解2024-04-0414.[ABC211F] Rectilinear Polygons 题解2024-04-0415.[ABC223F] Parenthesis Checking 题解2024-04-0416.CF154C Double Profiles 题解2024-04-1617.[ABC208D] Shortest Path Queries 2 题解2024-04-1718.[ABC212E] Safety Journey 题解2024-04-17

19.[ABC229E] Graph Destruction 题解2024-04-17

20.[ABC240E] Ranges on Tree 题解2024-04-1821.[ABC261E] Many Operations 题解2024-05-1222.P10842 【MX-J2-T3】Piggy and Trees 题解2024-08-05

收起

[ABC229E] Graph Destruction 题解

思路解析

题目要求删点，而众所周知删点的代价要大于加点的代价，于是我们考虑倒着处理询问，将每一个删点改成加点，而加点时就用并查集维护连通块即可。

code

#include<bits/stdc++.h>
using namespace std;
const int N = 2e5 + 10;
int n, m, fa[N];
vector<int> g[N];
int find(int x) {
	if(x == fa[x]) return x;
	return (fa[x] = find(fa[x]), fa[x]);
}
int main() {
	cin >> n >> m;
	for(int i = 1, u, v; i <= m; i++) {
		cin >> u >> v;
		g[u].push_back(v);
		g[v].push_back(u);
	}
	for(int i = 1; i <= n; i++) fa[i] = i;
	int ans = 0;
	stack<int> st;
	for(int i = n; i >= 1; i--) {
		st.push(ans);
		ans ++;
		for(auto it : g[i]) {
			if(it > i) {
				if(find(it) != find(i)) ans --;
				fa[find(it)] = find(i);
			}
		}
	}
	while(!st.empty()) cout << st.top() << '\n', st.pop();
	return 0;
}