Submission #1087752

#	Time	Username	Problem	Language	Result	Execution time	Memory
1087752		alexander707070	Duathlon (APIO18_duathlon)	C++14	0 / 100	36 ms	18012 KiB

count_triplets

#include<bits/stdc++.h>
#define MAXN 200007
using namespace std;

int n,m,a,b;
vector<int> v[MAXN];
long long sz[MAXN],sum[MAXN],ans;

void dfs(int x,int p){
    sz[x]=1;

    for(int i=0;i<v[x].size();i++){
        if(v[x][i]==p)continue;
        dfs(v[x][i],x);

        sum[x]+=sz[v[x][i]]*(sz[v[x][i]]-1);
        sz[x]+=sz[v[x][i]];
    }

    sum[x]+=(n-sz[x])*(n-sz[x]-1);
}

int main(){

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    cin>>n>>m;
    for(int i=1;i<=m;i++){
        cin>>a>>b;
        v[a].push_back(b);
        v[b].push_back(a);
    }

    if(m!=n-1)cout<<1/0;

    dfs(1,0);

    for(int i=1;i<=n;i++){
        ans+=(long long) (n-2)*(n-1)-sum[i];
    }

    cout<<ans<<"\n";

    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void dfs(int, int)':
count_triplets.cpp:12:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for(int i=0;i<v[x].size();i++){
      |                 ~^~~~~~~~~~~~
count_triplets.cpp: In function 'int main()':
count_triplets.cpp:36:22: warning: division by zero [-Wdiv-by-zero]
   36 |     if(m!=n-1)cout<<1/0;
      |                     ~^~

• 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