Submission #1160849

#	Time	Username	Problem	Language	Result	Execution time	Memory
1160849		Nonoze	Pipes (BOI13_pipes)	C++20	74.07 / 100	337 ms	80220 KiB

pipes

/*
*	Author: Nonoze
*	Created: Sunday 02/03/2025
*/
#include <bits/stdc++.h>
using namespace std;

#ifndef IN_LOCAL
	#define dbg(...)
#endif

// #define cout cerr << "OUT: "
#define endl '\n'
#define endlfl '\n' << flush
#define quit(x) return (void)(cout << x << endl)

template<typename T> void read(T& x) { cin >> x;}
template<typename T1, typename T2> void read(pair<T1, T2>& p) { read(p.first), read(p.second);}
template<typename T> void read(vector<T>& v) { for (auto& x : v) read(x); }
template<typename T1, typename T2> void read(T1& x, T2& y) { read(x), read(y); }
template<typename T1, typename T2, typename T3> void read(T1& x, T2& y, T3& z) { read(x), read(y), read(z); }
template<typename T1, typename T2, typename T3, typename T4> void read(T1& x, T2& y, T3& z, T4& zz) { read(x), read(y), read(z), read(zz); }
template<typename T> void print(vector<T>& v) { for (auto& x : v) cout << x << ' '; cout << endl; }

#define sz(x) (int)(x.size())
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()
#define make_unique(v) sort(all(v)), v.erase(unique(all(v)), (v).end())
#define pb push_back
#define mp(a, b) make_pair(a, b)
#define fi first
#define se second
#define cmin(a, b) a = min(a, b)
#define cmax(a, b) a = max(a, b)
#define YES cout << "YES" << endl
#define NO cout << "NO" << endl
#define QYES quit("YES")
#define QNO quit("NO")

#define int long long
#define double long double
const int inf = numeric_limits<int>::max() / 4;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
const int MOD = 1e9+7, LOG=20;



void solve();

signed main() {
	ios::sync_with_stdio(0);
	cin.tie(0);
	int tt=1;
	// cin >> tt;
	while(tt--) solve();
	return 0;
}




int n, k, m;
vector<int> a, ans;
vector<set<pair<int, int>>> adj;

void delete_leaves() {
	queue<int> q; for (int i=0; i<n; i++) if (sz(adj[i])==1) q.push(i);
	while (!q.empty()) {
		int u=q.front(); q.pop();
		if (sz(adj[u])!=1) continue;
		int v=adj[u].begin()->fi, id=adj[u].begin()->se;
		ans[id]=a[u], a[v]-=a[u];
		adj[v].erase({u, id}), adj[u].clear();
		if (sz(adj[v])==1) q.push(v);
	}
}


void solve() {
	read(n, m);
	a.clear(), a.resize(n); read(a);
	adj.clear(), adj.resize(n);
	vector<pair<int, int>> edges;
	for (int i=0; i<m; i++) {
		int u, v; read(u, v); u--, v--;
		edges.pb({u, v});
		adj[u].insert({v, i}), adj[v].insert({u, i});
	}
	ans.clear(), ans.resize(m);
	delete_leaves();
	int root=-1;
	for (int i=0; i<n; i++) {
		if (sz(adj[i])>2) quit(0);
		if (sz(adj[i])==2) root=i;
	}
	if (root!=-1) {
		vector<pair<int, int>> path;
		while (1) {
			if (sz(adj[root])==0) break;
			int u=adj[root].begin()->fi, id=adj[root].begin()->se;
			path.pb({root, id});
			adj[u].erase({root, id}), adj[root].clear();
			root=u;
		}
		dbg(path);
		n=sz(path);
		if (n%2==0) quit(0);
		for (int i=1; i<n; i++) {
			ans[path[i].se]+=a[path[i].fi];
			a[path[(i+1)%n].fi]-=a[path[i].fi], a[path[i].fi]=0;
		}
		dbg(ans, a);
		for (int i=0; i<n; i++) {
			if (i%2==0) ans[path[i].se]+=a[path[i].fi];
			else ans[path[i].se]-=a[path[i].fi];
		}
	}
	for (auto u: ans) cout << u*2 << endl;
}

• Subtask 1: 30 / 30
• Subtask 2: 44.0741 / 70