제출 #931602

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
931602		12345678	Duathlon (APIO18_duathlon)	C++17	23 / 100	1071 ms	1048576 KiB

count_triplets

#include <bits/stdc++.h>

using namespace std;

#define ll long long

const int nx=1e5+5;

ll n, m, u, v, vs[nx], sz[nx], res;
vector<int> d[nx];

void dfs(int u, int p)
{
    vs[u]=1;
    ll vl=0, sm=0;
    sz[u]=1;
    for (auto v:d[u]) if (v!=p) dfs(v, u), vl+=(sz[v]), sm+=(sz[v]*sz[v]), sz[u]+=sz[v];
    res+=(vl*vl-sm)/2;
}

void dfs2(int u, int p, int rtsz)
{
    for (auto v:d[u]) if (v!=p) res+=(rtsz-sz[v])*(sz[v]-1), dfs2(v, u, rtsz);
}

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>m;
    for (int i=0; i<m; i++) cin>>u>>v, d[u].push_back(v), d[v].push_back(u);
    for (int i=1; i<=n; i++) if (!vs[i]) dfs(i, i), dfs2(i, i, sz[i]);
    cout<<2*res;
}

• 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