Submission #252991

#	Time	Username	Problem	Language	Result	Execution time	Memory
252991		infinite_iq	Duathlon (APIO18_duathlon)	C++14	31 / 100	927 ms	1048580 KiB

count_triplets

#define fast ios_base::sync_with_stdio(0),cin.tie(0),cout.tie(0)
#include <bits/stdc++.h>
using namespace std;
#define sqr 340
#define mp make_pair
#define mid (l+r)/2
#define le node * 2 
#define ri node * 2 + 1 
#define pb push_back
#define ppb pop_back
#define fi first
#define se second
#define lb lower_bound
#define ub upper_bound
#define ins insert
#define era erase
#define C continue
#define mem(dp,i) memset(dp,i,sizeof(dp))
#define mset multiset
#define all(x) x.begin(), x.end()
#define gc getchar_unlocked
typedef long long ll;
typedef short int si;
typedef long double ld;
typedef pair<int,int> pi;
typedef pair<ll,ll> pll;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<pi> vpi;
typedef vector<pll> vpll;
typedef pair<double,ll>pdi;
const ll inf=1e18;
const ll mod=987654321;
const ld Pi=acos(-1);
ll n , m , ans , nodes , edges ;
vll v [100009] ;
ll dp [100009] , done [100009] ; ;
void calc ( int node ) {
        if ( done [node] ) return ;
        done [node] = 1 ;
        nodes ++ , edges += v [node] .size () ;
        for ( auto u : v [node] )
                calc ( u ) ;
}
void solve ( int node , int p ) {
        dp [node] = 1 ;
        for ( auto u : v [node] ) {
                if ( u == p ) C ;
                solve ( u , node ) ;
                dp [node] += dp [u] ;
        }
        ll sum = 0 , up = nodes - dp [node] ;
        for ( auto u : v [node] ) {
                if ( u == p ) C ;
                ans += up  * dp [u] * 2ll ;
                ans += sum * dp [u] * 2ll ;
                sum += dp [u] ;
        }
}
int main () {
        cin >> n >> m ;
        for ( int i = 0 ; i < m ; i ++ ) {
                int a , b ;
                cin >> a >> b ;
                a -- , b -- ;
                v [a] .pb ( b ) ;
                v [b] .pb ( a ) ;
        }
        for ( int i = 0 ; i < n ; i ++ ) {
                if ( done [i] ) C ;
                nodes = 0 , edges = 0 ;
                calc ( i ) ;
                if ( nodes * 2ll == edges ) {
                        if ( nodes >= 3ll ) {
                                ans += ( nodes ) * ( nodes - 1ll ) * ( nodes - 2ll ) ;
                        }
                }
                else
                        solve ( i , i ) ;
        }
        cout << ans << endl ;
}

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