Submission #674259

#	Time	Username	Problem	Language	Result	Execution time	Memory
674259		Jarif_Rahman	Duathlon (APIO18_duathlon)	C++17	0 / 100	1098 ms	1048576 KiB

count_triplets

#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

int n, m;
vector<vector<int>> graph;
vector<int> sz;
ll ans = 0;

int N = 0;
void dfs(int nd, int ss){
    N++;
    sz[nd] = 1;
    for(int x: graph[nd]) if(x != ss) dfs(x, nd), sz[nd]+=sz[x];
}
void dfs2(int nd, int ss){
    for(int x: graph[nd]) if(x != ss) dfs2(x, nd);

    ans+=ll(N-sz[nd])*ll(sz[nd]-1);
    for(int x: graph[nd]) if(x != ss) ans+=ll(N-sz[x]-1)*ll(sz[x]);
}

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

    cin >> n >> m;
    graph.resize(n);
    sz.resize(n, 0);

    for(int i = 0; i < m; i++){
        int a, b; cin >> a >> b; a--, b--;
        graph[a].pb(b);
        graph[b].pb(a);
    }

    for(int i = 0; i < 1; i++) if(!sz[i]){
        N = 0;
        dfs(i, -1);
        dfs2(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