Submission #106040

#	Time	Username	Problem	Language	Result	Execution time	Memory
106040		username	Duathlon (APIO18_duathlon)	C++14	0 / 100	1166 ms	893492 KiB

count_triplets

#pragma GCC optimize("O3")
#include<stdint.h>
#include<ext/pb_ds/assoc_container.hpp>
#include<ext/pb_ds/tree_policy.hpp>
#include<ext/rope>
using namespace __gnu_pbds;
using namespace __gnu_cxx;
#define VIS(it,con) for(auto it=con.begin();it!=con.end();++it)
#define pob pop_back
#define pf push_front
#define pof pop_front
#define MIN(x,y) (x=min(x,(y)))
#define MAX(x,y) (x=max(x,(y)))
#define mid ((l+r)/2)
#define lch (idx*2+1)
#define rch (idx*2+2)
/*****************************************************************************/
#include<bits/stdc++.h>
#define int int_fast64_t
using namespace std;
typedef pair<int,int> pii;
typedef vector<int> VI;
#define REP(i,j,k) for(register int i=(j);i<(k);++i)
#define RREP(i,j,k) for(register int i=(j)-1;i>=(k);--i)
#define ALL(a) a.begin(),a.end()
#define MST(a,v) memset(a,(v),sizeof a)
#define pb push_back
#define F first
#define S second
#define endl '\n'
//																#define __debug
#ifdef __debug
	#define IOS (void)0
	#define de(...) cerr<<__VA_ARGS__
	#define ar(a,s,t) {REP(__i,s,t)de(min((int)1e9-1,a[__i])<<' ');de(endl);}
#else
	#define IOS cin.tie(0),cout.tie(0),ios_base::sync_with_stdio(false)
	#define de(...) (void)0
	#define ar(...) (void)0
#endif
/***********************************default***********************************/
const int maxn=1e5+9;
int n,m,res=0,sz[maxn];
VI G[maxn];

void dfs(int u,int f){
	sz[u]=1;
	REP(i,0,G[u].size()){
		int v=G[u][i];
		if(v==f)continue;
		dfs(v,u);
		res+=2*sz[v]*(n-sz[v]-1);
		sz[u]+=sz[v];
	}
}

main(){
	IOS;
	cin>>n>>m;
	REP(i,0,m){
		int u,v;cin>>u>>v,--u,--v;
		G[u].pb(v),G[v].pb(u);
	}
	dfs(0,-1);
	cout<<res<<endl;
}

Compilation message (stderr)

count_triplets.cpp: In function 'void dfs(int_fast64_t, int_fast64_t)':
count_triplets.cpp:23:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define REP(i,j,k) for(register int i=(j);i<(k);++i)
                                            ^
count_triplets.cpp:48:2: note: in expansion of macro 'REP'
  REP(i,0,G[u].size()){
  ^~~
count_triplets.cpp: At global scope:
count_triplets.cpp:57:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main(){
      ^

• 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