Submission #744537

#	Time	Username	Problem	Language	Result	Execution time	Memory
744537		Abito	Duathlon (APIO18_duathlon)	C++14	23 / 100	1081 ms	1048576 KiB

count_triplets

#include <bits/stdc++.h>
#define pb push_back
#define F first
#define S second
#define endl '\n'
#define ep insert
#define pow pwr
#define sqrt sqrtt
#define elif else if
#define y1 YONE
#define int long long
#define ppb pop_back
using namespace std;
const int N=1e6+5;
int n,m,sz[N],par[N],dpar[N],dsz[N];
vector<int> adj[N],v;
set<pair<pair<int,int>,int>> s;
bool vis[N];
int getpar(int x){
    if (x==dpar[x]) return x;
    return dpar[x]=getpar(dpar[x]);
}
void link(int x,int y){
    x=getpar(x);y=getpar(y);
    if (x==y) return;
    if (dsz[x]>dsz[y]) swap(x,y);
    dpar[x]=y;
    dsz[y]+=dsz[x];
    return;
}
int getsize(int node,int p){
    par[node]=p;
    sz[node]=1;
    for (auto u:adj[node]){
        if (u==p) continue;
        sz[node]+=getsize(u,node);
    }return sz[node];
}
void backtrack(int node){
    v.pb(node);
    for (int i=0;i<v.size();i++){
        for (int j=i+1;j<v.size();j++){
            for (int k=j+1;k<v.size();k++) s.ep({{v[i],v[j]},v[k]});
        }
    }
    vis[node]=true;
    for (auto u:adj[node]){
        if (vis[u]) continue;
        backtrack(u);
    }
    v.ppb();
    vis[node]=false;
    return;
}
int32_t main(){
    //ios_base::sync_with_stdio(false);cin.tie(NULL);cout.tie(NULL);
    cin>>n>>m;
    if (n<=10){
        for (int i=1;i<=m;i++){
            int x,y;
            cin>>x>>y;
            adj[x].pb(y);
            adj[y].pb(x);
        }
        for (int i=1;i<=n;i++) backtrack(i);
        cout<<s.size()<<endl;
        //for (auto u:s) cout<<u.F.F<<' '<<u.F.S<<' '<<u.S<<endl;
        return 0;
    }
    for (int i=1;i<=n;i++){
        dsz[i]=1;
        dpar[i]=i;
    }
    for (int i=1;i<=m;i++){
        int x,y;
        cin>>x>>y;
        adj[x].pb(y);
        adj[y].pb(x);
        link(x,y);
    }
    for (int i=1;i<=n;i++){
        if (sz[i]) continue;
        getsize(i,0);
    }
    int ans=0;
    for (int i=1;i<=n;i++){
        int x=sz[i]-1;
        for (auto u:adj[i]){
            if (u==par[i]) continue;
            x-=sz[u];
            ans+=x*sz[u];
        }ans+=(dsz[getpar(i)]-sz[i])*(sz[i]-1);
    }
    cout<<ans*2LL<<endl;
    return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void backtrack(long long int)':
count_triplets.cpp:41:19: 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]
   41 |     for (int i=0;i<v.size();i++){
      |                  ~^~~~~~~~~
count_triplets.cpp:42:25: 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]
   42 |         for (int j=i+1;j<v.size();j++){
      |                        ~^~~~~~~~~
count_triplets.cpp:43:29: 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]
   43 |             for (int k=j+1;k<v.size();k++) s.ep({{v[i],v[j]},v[k]});
      |                            ~^~~~~~~~~

• 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