Submission #217576

#	Time	Username	Problem	Language	Result	Execution time	Memory
217576		VEGAnn	Duathlon (APIO18_duathlon)	C++14	23 / 100	1126 ms	1048580 KiB

count_triplets

#include <bits/stdc++.h>
#define PB push_back
using namespace std;
typedef long long ll;
const int N = 100100;
const int oo = 2e9;
vector<int> g[N];
int n, m, siz[N], SZ;
bool mrk[N];
ll ans = 0;

void dfs(int v, int p){
    siz[v] = 1;
    mrk[v] = 1;

    for (int u : g[v]){
        if (u == p) continue;
        dfs(u, v);
        siz[v] += siz[u];
    }
}

void DFS(int v, int p){
    ll sum = 0;

    for (int u : g[v]){
        if (u == p) continue;
        DFS(u, v);

        ans += sum * ll(siz[u]);
        sum += siz[u];
    }

    ans += sum * (ll(SZ) - ll(siz[v]));
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);

//    freopen("in.txt","r",stdin);

    cin >> n >> m;

    for (int i = 0; i < m; i++){
        int x, y; cin >> x >> y;
        x--; y--;
        g[x].PB(y);
        g[y].PB(x);
    }

    for (int i = 0; i < n; i++)
        if (!mrk[i]){
            dfs(i, -1);
            SZ = siz[i];
            DFS(i, -1);
        }

    cout << ans * 2;

    return 0;
}

• 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