Submission #137858

#	Time	Username	Problem	Language	Result	Execution time	Memory
137858		Osama_Alkhodairy	Circle selection (APIO18_circle_selection)	C++17	0 / 100	12 ms	9980 KiB

circle_selection

#include <bits/stdc++.h>
using namespace std;
#define finish(x) return cout << x << endl, 0
#define ll long long

const int N = 200001;

int n, m;
vector <int> v[N];
ll ans;

int dfs(int node, int pnode){
    int ret = 1;
    for(auto &i : v[node]){
        if(i == pnode) continue;
        int cur = dfs(i, node);
        ret += cur;
        ans += 1LL * cur * (n - cur);
    }
    return ret;
}
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> n >> m;
    for(int i = 0 ; i < m ; i++){
        int x, y;
        cin >> x >> y;
        v[x].push_back(y);
        v[y].push_back(x);
    }
    dfs(1, 0);
    ans *= 2;
    ans -= 2LL * n * (n - 1) / 2;
    cout << ans << endl;
}

• Subtask 1: 0 / 7
• Subtask 2: 0 / 12
• Subtask 3: 0 / 15
• Subtask 4: 0 / 23
• Subtask 5: 0 / 30
• Subtask 6: 0 / 13