Submission #673478

#	Time	Username	Problem	Language	Result	Execution time	Memory
673478		Lobo	Pipes (BOI13_pipes)	C++17	74.07 / 100	239 ms	45700 KiB

pipes

#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 5e5+10;

int n, m, c[maxn], ans[maxn], gr[maxn];
vector<pair<int,int>> g[maxn];

void solve() {
    cin >> n >> m;
    for(int i = 1; i <= n; i++) {
        cin >> c[i];
    }
    for(int i = 1; i <= m; i++) {
        int u,v; cin >> u >> v;
        g[u].pb(mp(v,i));
        g[v].pb(mp(u,i));
        gr[u]++;
        gr[v]++;
    }

    if(m != n-1) {
        cout << 0 << endl;
        return;
    }
    if(n == 2) {
        cout << 2*c[1] << endl;
        return;
    }
    queue<int> q;
    for(int i = 1; i <= n; i++) {
        if(gr[i] == 1) q.push(i);
    }


    while(q.size()) {
        int u = q.front(); q.pop();
        gr[u] = -1;
        for(auto V : g[u]) {
            int v = V.fr;
            int id = V.sc;
            if(gr[v] == -1) continue;
            ans[id] = 2*c[u];
            c[v]-= c[u];
            if(--gr[v] == 1) q.push(v);
        }
    }

    for(int i = 1; i <= m; i++) {
        cout << ans[i] << endl;
    }
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

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