Submission #1201770

#TimeUsernameProblemLanguageResultExecution timeMemory
1201770crispxx새 집 (APIO18_new_home)C++20
0 / 100
3 ms7492 KiB
#include <bits/stdc++.h>
using namespace std;

#define int long long
#define all(x) x.begin(), x.end()
#define pb push_back
#define ar array
#define nl '\n'

template <typename A, typename B>
bool chmin(A &a, const B &b) {
	if(a > b) {
		return a = b, true;
	}
	return false;
}

template <typename A, typename B>
bool chmax(A &a, const B &b) {
	if(a < b) {
		return a = b, true;
	}
	return false;
}

void solve() {
	int n, m; cin >> n >> m;
	
	vector<vector<int>> adj(n);
	
	vector<pair<int, int>> edges;
	
	for(int i = 0; i < m; i++) {
		int u, v; cin >> u >> v;
		adj[--u].pb(--v);
		adj[v].pb(u);
		edges.pb({u, v});
	}
	
	auto solve1 = [&]() {
		int ans = 0;
		
		for(int u = 0; u < n; u++) {
			queue<int> q;
			vector<int> d(n, -1), sum(n);
			q.emplace(u);
			d[u] = 0;
			while(!q.empty()) {
				int v = q.front();
				q.pop();
				ans += sum[v];
				for(auto to : adj[v]) {
					if(d[to] == -1) {
						d[to] = d[v] + 1;
						sum[to] += d[v];
						q.emplace(to);
					}
				}
			}
		}
		
		return ans;
	};
	
	vector<int> s(n, 1), used(n);
	
	int ans = 0;
	
	auto dfs = [&](auto &&self, int v, int p, vector<int> &output) -> void {
		used[v] = true;
		for(auto to : adj[v]) {
			if(to == p) continue;
			self(self, to, v, output);
			s[v] += s[to];
		}
		output.pb(v);
	};
	
	vector<int> output;
	
	auto solve2 = [&]() {
		for(int i = 0; i < n; i++) {
			if(!used[i]) {
				output.clear();
				dfs(dfs, i, -1, output);
				for(auto v : output) {
					for(auto to : adj[v]) {
						ans += s[to] * (s[i] - 1 - s[to]);
					}
				}
			}
		}
	};
	
	auto print = [&](int x) {
		cout << x << nl;
	};
	
	if(n <= 1000) {
		print(solve1());
		return;
	}
	
	solve2();
	
	cout << ans << nl;
}

/**
4 3
1 2
2 3
3 4

4 4
1 2
2 3
3 4
4 2

**/

signed main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr);
	
	solve();
}
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...
#Verdict Execution timeMemoryGrader output
Fetching results...