Submission #1088521

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088521		alexander707070	Duathlon (APIO18_duathlon)	C++14	0 / 100	102 ms	30668 KiB

count_triplets

#include<bits/stdc++.h>
#define MAXN 200007
using namespace std;

int n,m,a[MAXN],b[MAXN],k;
int dp[MAXN],low[MAXN];

vector< pair<int,int> > v[MAXN];
vector<int> g[MAXN];
stack<int> st;

int li[MAXN],tim,sz[MAXN];

long long ans;

void bcc(int x,int p,int dep){
	st.push(x);
	li[x]=tim; dp[x]=low[x]=dep;
	
	int ch=0;

	for(int i=0;i<v[x].size();i++){
		if(li[v[x][i].first]!=tim){
			bcc(v[x][i].first,x,dep+1); ch++;
			low[x]=min(low[x],low[v[x][i].first]);

			if(low[v[x][i].first]>=dp[x]){
				k++;
				g[k].push_back(x);
				g[x].push_back(k);

				cout<<k<<" "<<x<<"\n";

				while(!st.empty()){
					cout<<st.top()<<" "<<k<<"\n";
					g[st.top()].push_back(k);
					g[k].push_back(st.top());

					if(st.top()==v[x][i].first){
						st.pop(); break;
					}
					st.pop();
				}
			}

		}else if(v[x][i].first!=p){
			low[x]=min(low[x],dp[v[x][i].first]);
		}
	}
}

void dfs(int x,int p){
	sz[x]=(x<=n);

	for(int i=0;i<g[x].size();i++){
		if(g[x][i]==p)continue;
		dfs(g[x][i],x);

		sz[x]+=sz[g[x][i]];
	}
}

void dfs2(int x,int p,int szcomp){
	for(int i=0;i<g[x].size();i++){
		if(g[x][i]==p)continue;
		dfs2(g[x][i],x,szcomp);

		if(x>n)ans-=(long long) (g[x].size()-1) * (sz[g[x][i]]-1) * (sz[g[x][i]]);
	}

	if(x>n)ans-=(long long) (g[x].size()-1) * (szcomp-sz[x]-1) * (szcomp-sz[x]);
}

int main(){

	ios_base::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);

	cin>>n>>m;
	for(int i=1;i<=m;i++){
		cin>>a[i]>>b[i];

		v[a[i]].push_back({b[i],i});
		v[b[i]].push_back({a[i],i});
	}

	tim++; k=n;
	for(int i=1;i<=n;i++){
		if(li[i]!=tim)bcc(i,0,0);
	}

	tim++;
	for(int i=1;i<=k;i++){
		if(sz[i]!=0)continue;

		dfs(i,0);
		ans+=(long long) sz[i]*(sz[i]-1)*(sz[i]-2);
		dfs2(i,0,sz[i]);
	}

	cout<<ans<<"\n";

	return 0;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void bcc(int, int, int)':
count_triplets.cpp:22:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   22 |  for(int i=0;i<v[x].size();i++){
      |              ~^~~~~~~~~~~~
count_triplets.cpp: In function 'void dfs(int, int)':
count_triplets.cpp:55:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~
count_triplets.cpp: In function 'void dfs2(int, int, int)':
count_triplets.cpp:64:15: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |  for(int i=0;i<g[x].size();i++){
      |              ~^~~~~~~~~~~~

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