Submission #124967

#	Time	Username	Problem	Language	Result	Execution time	Memory
124967		elabensaad	철인 이종 경기 (APIO18_duathlon)	C++14	23 / 100	1146 ms	1048580 KiB

count_triplets

#include <bits/stdc++.h>

using namespace std;

long long n, m, x, y, vis[300000], ans;
vector <int> t[300000];

void DFS (int v){
	vis[v] = 1;
	for (auto i : t[v]){
		if (vis[i] == 0){DFS(i);vis[v] += vis[i];
		}
	}
}
void dfs (int v, int r, int p = 0){
	ans+=(vis[r]-vis[v])*(vis[v]-1)*2;
	for (auto i : t[v]){
		if (i != p){dfs(i, r, v);ans+=(vis[v]-vis[i]-1)*vis[i];}
	}
}

main() {
	cin >> n >> m;
	for(int i = 0;i < m;i++){
		cin >> x >> y;
		x--;
		y--;
		t[x].push_back(y);
		t[y].push_back(x);	
	}
	for (int i = 0; i < n; i++){
		if (vis[i] == 0){
			DFS(i);		
			dfs(i, i);
		}
	}
	cout << ans;
}

Compilation message (stderr)

count_triplets.cpp:22:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main() {
      ^

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 0 / 8
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 0 / 15
• Subtask 7: 0 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10