Submission #262238

#	Time	Username	Problem	Language	Result	Execution time	Memory
262238		Rouge_Hugo	Duathlon (APIO18_duathlon)	C++14	66 / 100	208 ms	33144 KiB

count_triplets

#include<bits/stdc++.h>
#define fi first
#define ll long long
#define pb push_back
#define se second
using namespace std;
int n,m;
ll re=0;
int szz=0;
const int N=200009;
vector<pair<int,int>>v[N];
vector<pair<int,int>>v1[N];
ll cnt=1,t[N],num[N],a[N],low[N],bridge[N],b[N],par[N],vis[N],sz[N],bo[N];
int tt=0;
vector<int>nd;
void dfs (int x,int p)
{
    nd.pb(x);
    vis[x]=1;
    low[x]=num[x]=++tt;
    for(auto it:v[x])
    {
        if (num[it.first]==0)
            dfs(it.first,x);
        if (num[x]<low[it.first])
            bridge[it.second]=1;
        if (it.first!=p)
            low[x]=min(low[x],low[it.first]);
    }
        if(low[x] == num[x]) {
            int w=1;
        while(nd.back() != x) {
            par[nd.back()] = cnt;
            nd.pop_back();w++;
        }
        par[nd.back()] = cnt;
        nd.pop_back();
        bo[cnt]=w;
        cnt++;
    }
}
void dfs2(int x,int p)
{
    vis[x]=1;
    for(auto it:v[x])
    {
        if(it.fi==p)continue;
        if (!vis[it.first])
            dfs2(it.first,x);
        if (bridge[it.second]==1)
        {
            v1[par[x]].push_back({par[it.fi],x});
            v1[par[it.fi]].push_back({par[x],it.fi});
        }
    }
}
void solve(int x,int p)
{
    vis[x]=1;
    for(auto it:v1[x])
    {
        if(it.fi==p)continue;
        solve(it.fi,x);
        sz[x]+=sz[it.fi];
    }
    sz[x]+=bo[x];
}
void go (int x,int p,ll up)
{
    vis[x]=1;
    sz[x]-=bo[x];
    if(bo[x]>=3)
        re+=bo[x]*(bo[x]-1)*(bo[x]-2);
    re+=(up)*((bo[x])-1)*((bo[x])-1)*2;
    re+=(sz[x])*(bo[x]-1)*(bo[x]-1)*2;int u=0;
    for(auto it:v1[x])
    {
        if(it.fi==p)
        {
            u=it.se;
        }
        if(it.fi==p)continue;
        re+=2*(t[x]-a[it.se])*sz[it.fi]*(bo[x]);
        re+=2*a[it.se]*sz[it.fi];
        a[it.se]+=sz[it.fi];
        t[x]+=sz[it.fi];
        go(it.fi,x,up+bo[x]+sz[x]-sz[it.fi]);
    }
    re+=2*up*bo[x]*(sz[x]-a[u]);
    re+=2*up*a[u];
}
int main()
{
    ios::sync_with_stdio(0);cin.tie(0);cout.tie(0);
    scanf("%d %d", &n, &m);
    int x,y;
    for(int i=0; i<m; i++)
    {
        scanf("%d %d", &x, &y);
        v[x].push_back({y,i});
        v[y].push_back({x,i});
    }
    memset (vis,0,sizeof vis);
    for(int i=1;i<n+1;i++)
    {
        if(vis[i])continue;
        dfs(i,-1);
    }
    memset (vis,0,sizeof vis);
    for(int i=1;i<n+1;i++)
    {
        if(vis[i])continue;
        dfs2(i,-1);
    }
    memset (vis,0,sizeof vis);
    for(int i=1;i<cnt;i++)
    {
        if(vis[i])continue;
        solve(i,0);
    }
    re=0;
    memset (vis,0,sizeof vis);
    for(int i=1;i<cnt;i++)
    {
        if(vis[i])continue;
        go(i,0,0);
    }
    cout<<re;
}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:95:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   95 |     scanf("%d %d", &n, &m);
      |     ~~~~~^~~~~~~~~~~~~~~~~
count_triplets.cpp:99:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   99 |         scanf("%d %d", &x, &y);
      |         ~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 11
• Subtask 3: 8 / 8
• Subtask 4: 10 / 10
• Subtask 5: 13 / 13
• Subtask 6: 15 / 15
• Subtask 7: 20 / 20
• Subtask 8: 0 / 8
• Subtask 9: 0 / 10