Submission #120725

#	Time	Username	Problem	Language	Result	Execution time	Memory
120725		_demon_	Duathlon (APIO18_duathlon)	C++14	23 / 100	1148 ms	1048576 KiB

count_triplets

    #include <bits/stdc++.h>
    using namespace std;
    typedef long long ll;
    ll n,m;
    ll child[100009];
    ll ans;
    ll w[100009];
    vector<ll>v[100009];
    int done[100009];
    int comp[100009];
    int mp[1000009];
    int crnt=0;
    void dfs1(int node,int p){
        child[node]=1;
        done[node]=1;
        comp[node]=crnt;
        mp[crnt]++;
        if(node!=p)w[node]=w[p]+1;
        for(int i=0;i<v[node].size();i++){
            int u=v[node][i];
            if(u==p)continue;
            dfs1(u,node);
            child[node]+=child[u];
        }
    }
    int a[100009];
    void dfs2(int node,int p){
        done[node]=1;
        ll sum=0;
        for(int i=0;i<v[node].size();i++){
            int u=v[node][i];
            if(w[u]>w[node]){
                sum+=child[u]*(mp[comp[node]]-child[u]-1);
            }
            else{
                sum+=(mp[comp[node]]-child[node])*(child[node]-1);
            }
        }
        a[node]=sum;
        ans+=sum;
        for(int i=0;i<v[node].size();i++){
            int u=v[node][i];
            if(u==p)continue;
            dfs2(u,node);
        }
    }
    int main(){
        cin>>n>>m;
        for(int i=0;i<m;i++){
            int a,b;
            cin>>a>>b;
            a--;b--;
            v[a].push_back(b);
            v[b].push_back(a);
        }
        for(int i=0;i<n;i++){
            if(done[i]==0){
                dfs1(i,i);
                crnt++;
            }
        }
        memset(done,0,sizeof(done));
        for(int i=0;i<n;i++){
            if(done[i]==0){
              dfs2(i,i);
            }
        }
    /*  for(int i=0;i<n;i++){
            cout<<a[i]<<" ";
        }
    cout<<endl;*/
        cout<<ans<<endl;
    }

Compilation message (stderr)

count_triplets.cpp: In function 'void dfs1(int, int)':
count_triplets.cpp:19:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<v[node].size();i++){
                     ~^~~~~~~~~~~~~~~
count_triplets.cpp: In function 'void dfs2(int, int)':
count_triplets.cpp:30:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<v[node].size();i++){
                     ~^~~~~~~~~~~~~~~
count_triplets.cpp:41:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<v[node].size();i++){
                     ~^~~~~~~~~~~~~~~

• 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