Submission #50896

#	Time	Username	Problem	Language	Result	Execution time	Memory
50896		hamzqq9	Duathlon (APIO18_duathlon)	C++14	100 / 100	228 ms	34564 KiB

count_triplets

#include<bits/stdc++.h>
#define lf double
#define ll long long
#define ull unsigned ll
#define ii pair<int,int>
#define li pair<ll,int>
#define iii pair<ii,int>
#define iiii pair<ii,ii>
#define iiii2 pair<int,iii>
#define lii pair<ll,ii>
#define lolo pair<ll,ll>
#define heap priority_queue
#define mp make_pair
#define st first
#define nd second
#define pb push_back
#define pf push_front
#define ppb pop_back
#define ppf pop_front
#define all(x) x.begin(),x.end()
#define len(x) strlen(x)
#define sz(x) (int) x.size()
#define orta ((bas+son)/2)
#define min3(x,y,z) min(min(x,y),z)
#define max3(x,y,z) max(max(x,y),z)
#define umin(x,y) x=min(x,y)
#define umax(x,y) x=max(x,y)
#define dbgs(x) cerr<<(#x)<<" --> "<<(x)<<" "
#define dbg(x) cerr<<(#x)<<" --> "<<(x)<<endl;getchar()
#define MOD 1000000007
#define inf 1000000000
#define N 200005
#define LOG 20
#define magic 100
#define KOK 350
#define EPS 0.0025
#define pw(x) ((1ll)<<(x))
#define PI 3.1415926535
#define get(x,y) ((x<0)?(x+y):(x))
using namespace std;

int n,m,x,y,bcc,t,sz;
int total[N],vis[N],low[N],Ap[N];
vector<int> Nodes[N],Gr[N],v[N];
ll ans;
stack<int> S;

void dfs(int B,int ata) {

	int sum=total[B]+sz(Nodes[B]);

	for(int i:Nodes[B]) {

		dfs(i,B);

		total[B]+=total[i];

		if(B>n) ans-=1ll*sum*total[i]*(total[i]-1);

	}

	if(B>n) ans-=1ll*sum*(sz-total[B])*(sz-total[B]-1);

}

void found(int x,int node) {

	for(int temp=-1;temp!=x;) {

		temp=S.top();

		S.pop();

		if(Ap[temp]) Nodes[bcc].pb(temp);
		else total[bcc]++;

	}

	Ap[node]++;

	total[node]=1;

	Nodes[node].pb(bcc);

}

void bccF(int node,int ata) {

	vis[node]=low[node]=++t;

	sz++;

	Ap[node]=(ata==-1?-1:0);

	for(int i:v[node]) {

		if(i==ata) continue ;

		if(!vis[i]) {

			S.push(i);

			bccF(i,node);

			umin(low[node],low[i]);

			if(low[i]>=vis[node]) {

				bcc++;

				found(i,node);

			}
		
		}
		else {

			umin(low[node],vis[i]);

		}

	}

}

int main() {

 	#if 0
	freopen("input.txt","r",stdin);
 	#endif

	scanf("%d %d",&n,&m);

	for(int i=1;i<=m;i++) {

		scanf("%d %d",&x,&y);

		v[x].pb(y);
		v[y].pb(x);

	}

	bcc=n;

	for(int i=1;i<=n;i++) {

		if(!vis[i]) {

			sz=0;

			S.push(i);

			bccF(i,-1);

			S.pop();

			ans+=1ll*sz*(sz-1)*(sz-2);

			if(Ap[i]) dfs(i,-1);
			else {

//				total[Nodes[i][0]]++;

				dfs(Nodes[i][0],-1);

			}

		}

	}

	printf("%lld",ans);

}

Compilation message (stderr)

count_triplets.cpp: In function 'int main()':
count_triplets.cpp:132:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d %d",&n,&m);
  ~~~~~^~~~~~~~~~~~~~~
count_triplets.cpp:136:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d",&x,&y);
   ~~~~~^~~~~~~~~~~~~~~

• 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