제출 #329299

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
329299		nickmet2004	Duathlon (APIO18_duathlon)	C++11	0 / 100	640 ms	1048576 KiB

count_triplets

#include<bits/stdc++.h>

using namespace std;
const int N = 1e5 + 5;
int n , m;
vector<int> adj[N];
int sub[N] , ans[N];
void go(int u = 1 , int p = 0){
    for(int v : adj[u]){
        if(v==p)continue;
        go(v , u);
        sub[u] += sub[v];
    }
    sub[u]++;
}
void dfs(int u = 1, int p = 0){
    for(int v : adj[u]){
        if(v == p)continue;
        dfs(v , u);
        if(adj[v].size() > 1) ans[u] += sub[v] - 1 + ans[v];
    }
}
int main (){
    ios_base::sync_with_stdio(0); cin.tie(0);
    cin >> n >> m;
    for(int i = 1; i < n; ++i){
        int u , v; cin >>u >> v;
        adj[u].emplace_back(v); adj[v].emplace_back(u);
    }
    go();
    dfs();
    int A = 0;
    for(int i = 1; i <= n; ++i) A += ans[i];
    cout << A * 2;

}

• 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