Submission #927766

#	Time	Username	Problem	Language	Result	Execution time	Memory
927766		TAhmed33	Duathlon (APIO18_duathlon)	C++98	0 / 100	79 ms	16564 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
#define int long long
int n;
vector <int> adj[300001];
int sze[300001];
bool vis[300001];
void calc (int pos, int par) {
  	vis[pos] = 1;
	for (auto j : adj[pos]) {
		if (j == par) continue;
		calc(j, pos);
		sze[pos] += sze[j];
	}
	sze[pos]++;
}
int ans = 0;
void dfs (int pos, int par) {
  	vis[pos] = 1;
    ans += 2 * (n - sze[pos]) * (sze[pos] - 1);
    int cur = 0;
    for (auto j : adj[pos]) {
        if (j == par) continue;
        ans += 2 * sze[j] * cur;
        cur += sze[j];
        dfs(j, pos);
    }
}
signed main () {
    cin >> n; int m; cin >> m; assert(m == n - 1);
    for (int i = 1; i <= m; i++) {
	    int a, b;
	    cin >> a >> b;
	    adj[a].push_back(b);
	    adj[b].push_back(a);
    }
    for (int i = 1; i <= n; i++) if (!vis[i]) calc(i, -1);
    memset(vis, 0, sizeof(vis));
  	for (int i = 1; i <= n; i++) if (!vis[i]) dfs(i, -1);
  	cout << ans << '\n';
}

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