Submission #221953

#	Time	Username	Problem	Language	Result	Execution time	Memory
221953		infinite_iq	Pipes (BOI13_pipes)	C++14	74.07 / 100	855 ms	97572 KiB

pipes

#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 mid (l+r)/2
#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
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;
const ll inf=1e18;
const ld pai=acos(-1);
ll n , m , all ;
set<pll>v[500009];
ll val[500009] , ans[500009] , ret[500009] , VAL[500009] ,done[500009];;
ll start , sum , xxx ;
void dfs ( int node , int p ) {
        done [node] = 1;
        for ( auto u : v[node] ) {
                if ( u.fi == p ) C ;
                ll XXX = xxx ;
                if ( node != start ) XXX = -VAL[node];
                VAL[node] += XXX;
                VAL[u.fi] += XXX ;
                sum += XXX ;
                ret [ u.se ] = XXX ;
                if ( done[u.fi] ) C ;
                dfs ( u.fi , node ) ;
                break;
        }
}
int main () {
        mem ( ret , -1 ) ;
        cin >> n >> m ;
        for ( int i = 0 ; i < n ; i ++ ) cin >> val[i] , all += val[i];
        all /= 2 ;
        for ( int i = 0 ; i < m ; i ++ ) {
                int a , b ;
                cin >> a >> b ;
                a -- , b -- ;
                v[a].ins( { b , i } ) ;
                v[b].ins( { a , i } ) ;
        }
        if ( m > n ) {
                cout << 0 << endl ;
                exit ( 0 ) ;
        }
        set<pll>s;
        for ( int i = 0 ; i < n ; i ++ ) {
                s.ins ( { v[i].size() , i } ) ;
        }
        while ( ( s.size() && s.begin()->fi==1 ) ) {
                int node = s.begin() -> se ;
                int to = v[node].begin() -> fi ;
                int id = v[node].begin() -> se ;
                s.era(s.begin());
                v[node].era( v[node].begin() );
                s.era ( { v[to].size() , to } ) ;
                v[to].era( { node , id } ) ;
                if ( v[to].size() ) s.ins ( { v[to].size() , to } ) ;
                ans [ id ] = - val [ node ] ;
                val [ to ] += ans [id] ;
                val [ node ] = 0 ;
        }
        if ( s.size() && s.size() % 2 == 0 ) cout << 0 << endl , exit ( 0 ) ;
        if ( !s.size() ) {
                for ( int i = 0 ; i < m ; i ++ ) {
                        cout << -ans [i] *2 << endl ;
                }
                exit ( 0 ) ;
        }
        for ( auto u : s ) VAL[u.se] = val[u.se] ;
        start = s.begin()->se;
        xxx = 0 ;
        dfs(start,start);
        for ( auto u : s ) VAL[u.se] = val[u.se] ;
        xxx = all + sum ;
        xxx *= -1 ;
        mem(done,0);
        dfs(start,start);
        for ( int i = 0 ; i < m ;i ++ ) {
                if ( ret[i]!=-1 ) cout << ret[i]*2<<endl;
                else cout << -ans [i]*2 << endl;
        }
}

• Subtask 1: 30 / 30
• Subtask 2: 44.074074074074076 / 70