Submission #815810

#	Time	Username	Problem	Language	Result	Execution time	Memory
815810		Ozy	Duathlon (APIO18_duathlon)	C++17	0 / 100	21 ms	5680 KiB

count_triplets

#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define debug(a) cout << #a <<  " = " << a << endl
#define debugsl(a) cout << #a << " = " << a << ", "
#define rep(i,a,b) for(int i = (a); i <= (b); i++)
#define repa(i,a,b) for(int i = (a); i >= (b); i--)
#define pll pair<lli,lli> 

#define MAX 100000

lli n,m,a,b,tam,res;
vector<lli> hijos[MAX+2];
lli vis[MAX+2];

bool ciclo(lli pos, lli padre) {

    tam++;
    vis[pos]=1;
    for(auto h : hijos[pos]) {
        if (h == padre) continue;
        if (vis[h]) return true;
        return ciclo(h,pos);
    }
    return false;
}

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

    cin >> n >> m;

    rep(i,1,m) {
        cin >> a >> b;
        hijos[a].push_back(b);
    }

    rep(i,1,n) {
        if(vis[i]) continue;
        tam = 0;
        if (ciclo(i,0)) a = (tam*(tam-1)*(tam-2))/2;
        else a = (tam*(tam-1)*(tam-2))/3;
        res += a;
    }

    cout << res;

    return 0;
}

• 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