Submission #747726

#	Time	Username	Problem	Language	Result	Execution time	Memory
747726		1075508020060209tc	Duathlon (APIO18_duathlon)	C++14	23 / 100	156 ms	47340 KiB

count_triplets

#include <bits/stdc++.h>

using namespace std;
#define int long long

int n;int m;
vector<int>e[300005];
vector<int>tr[300005];
vector<int>bke[300005];
vector<int>dwe[300005];
int sz[300005];int vis[300005];int dph[300005];int fa[300005];
int ans;

void fdfs(int nw){
vis[nw]=1;
sz[nw]=1;
for(int i=0;i<e[nw].size();i++){
    int v=e[nw][i];
    if(vis[v]==0){
        fa[v]=nw;
        dph[v]=dph[nw]+1;
        tr[nw].push_back(v);
        fdfs(v);
        sz[nw]+=sz[v];
        continue;
    }
    if(v==fa[nw]){continue;}
    if(dph[v]<dph[nw]){
        bke[nw].push_back(v);
        dwe[v].push_back(nw);
    }
}
}


void dfs1(int nw,int rtsz){
ans+=(rtsz-sz[nw])*(sz[nw]-1);
for(int i=0;i<tr[nw].size();i++){
    int v=tr[nw][i];
    dfs1(v,rtsz);
    ans+=sz[v]*(rtsz-1-sz[v]);
}
}

int bv;
pair<int,int> dfs2(int nw,int rtsz){
pair<int,int>ret={0,0};
for(int i=0;i<tr[nw].size();i++){
    int v=tr[nw][i];
    pair<int,int>vl=dfs2(v,rtsz);
    if(vl.first){
        ret=vl;
        ans+=(sz[v]-vl.first)*2;
    }
}
if(bke[nw].size()){
    ret={sz[nw],bke[nw][0]};
    //bv=bke[nw][0];
}
if(dwe[nw].size()){
    ret={0,0};
}

if(ret.first){
    ans+=(rtsz-sz[ret.second]+1)*(dph[nw]-dph[ret.second]-1)*2;
}


//cout<<nw<<" "<<ret<<endl;
return ret;
}



signed main()
{
    cin>>n>>m;
    for(int i=1;i<=m;i++){
        int a;int b;
        cin>>a>>b;
        e[a].push_back(b);
        e[b].push_back(a);
    }
    ans=0;
    vector<int>rt;
    for(int i=1;i<=n;i++){
        if(vis[i]==0){
            rt.push_back(i);
            fdfs(i);
        }
    }
    for(int i=0;i<rt.size();i++){
        dfs1(rt[i],sz[rt[i]]);
        dfs2(rt[i],sz[rt[i]]);
    }
    cout<<ans<<endl;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void fdfs(long long int)':
count_triplets.cpp:17:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   17 | for(int i=0;i<e[nw].size();i++){
      |             ~^~~~~~~~~~~~~
count_triplets.cpp: In function 'void dfs1(long long int, long long int)':
count_triplets.cpp:38:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 | for(int i=0;i<tr[nw].size();i++){
      |             ~^~~~~~~~~~~~~~
count_triplets.cpp: In function 'std::pair<long long int, long long int> dfs2(long long int, long long int)':
count_triplets.cpp:48:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   48 | for(int i=0;i<tr[nw].size();i++){
      |             ~^~~~~~~~~~~~~~
count_triplets.cpp: In function 'int main()':
count_triplets.cpp:92:18: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |     for(int i=0;i<rt.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