Submission #440100

#	Time	Username	Problem	Language	Result	Execution time	Memory
440100		KULIKOLD	Duathlon (APIO18_duathlon)	C++17	100 / 100	211 ms	26180 KiB

count_triplets

//#pragma GCC optimize ("O3")
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
#define endl '\n'
const int DIM = 1E5+7;
const int INF = 1E9;
vector<int> G[DIM];
vector<pair<int,int> > NG[DIM];

int depth[DIM],ptr = 0,P[DIM],vis[DIM],sub[DIM];
ll dp[DIM];
vector<int> V[DIM];
int fcmp(int v,int par){
    depth[v] = depth[par]+1;
    int mi = depth[v];
    for(auto to:G[v]){
        if (to==par)
            continue;
        if (depth[to]){
            if (depth[to]<depth[v])
                mi = min(mi,depth[to]);
            continue;
        }
        mi = min(mi,fcmp(to,v));
    }
    if (v!=par && mi<depth[par])
        P[v] = par;
    else if (v!=par && mi==depth[par]) {
        P[v] = v;
        V[v].push_back(par);
        NG[par].push_back({v, 0});
    }
    else {
        P[v] = v;
        if (v!=par)
        NG[par].push_back({v,1});
    }
    return mi;
}
int F(int x){
    return x==P[x]?x:P[x] = F(P[x]);
}
ll res = 0,ans = 0;

void dfs(int v){
    vis[v] = 1;
    int sz = int(V[v].size());
    dp[v] = ll(sz-1)*(sz-2) + sz - 1;
    ans+=ll(sz)*(sz-1)*(sz-2);
    sub[v] = sz;
    for(int ver:V[v]){
        if (F(ver)!=v)
            continue;
        int su = 0;
        for(auto [vto,type]:NG[ver]){
            int to = F(vto);
            if (to==v || vis[to])
                continue;
            dfs(to);
            if (type==1) {
                res += dp[to] * sub[v] + dp[v] * sub[to];
                dp[v] = dp[v] + dp[to] + sub[to];
                sub[v] += sub[to];
                su += sub[to];
            }
            else{
                res += dp[to]*(sub[v]-1)+dp[v]*(sub[to]-1)-ll(sub[to]-1)*(sub[v]-1);
                dp[v] = dp[v] + dp[to];
                sub[v]+=sub[to]-1;
                su+=sub[to]-1;
            }
        }
        dp[v]+=ll(sz-1)*su;
    }
    /*for(auto to:G[v]){
        if (vis[to])
            continue;
        dfs(to);
        res+=dp[to]*sub[v]+dp[v]*sub[to];
        dp[v] = dp[v]+dp[to]+sz*sub[to];
        sub[v]+=sub[to];
    }*/
}
int solve(){
    int n,m;
    cin>>n>>m;
    for(int i = 1;i<=m;++i){
        ll u,v;
        cin>>u>>v;
        G[u].push_back(v);
        G[v].push_back(u);
    }
    for(int i = 1;i<=n;++i){
        if (!P[i]) {
            fcmp(i, i);
        }
    }
    for(int i = 1;i<=n;++i){
        V[F(i)].push_back(i);
    }
    for(int i = 1;i<=n;++i){
        if (!V[i].empty() && !vis[i])
            dfs(i);
    }
    cout<<res*2+ans<<endl;
    return 1;
}
int main() {

    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);
    solve();
    return 0;
}

• Subtask 1: 5 / 5
• Subtask 2: 11 / 11
• Subtask 3: 8 / 8
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 15 / 15
• Subtask 7: 20 / 20
• Subtask 8: 8 / 8
• Subtask 9: 10 / 10