Submission #631459

#	Time	Username	Problem	Language	Result	Execution time	Memory
631459		TranGiaHuy1508	Pipes (BOI13_pipes)	C++17	100 / 100	192 ms	41932 KiB

pipes

/*
	Unknown's C++ Template (v3.2)
*/

#include "bits/stdc++.h"
using namespace std;

#define int long long

using ll = long long;
using ld = long double;
using ii = pair<int, int>;
using vi = vector<int>;
using vii = vector<ii>;
using vvi = vector<vi>;
using vvii = vector<vii>;
template <class T> using maxpq = priority_queue<T>;
template <class T> using minpq = priority_queue<T, vector<T>, greater<T>>;

#define pb push_back
#define all(x) x.begin(), x.end()
#define sz(x) (int)x.size()
#define mid ((l+r)>>1)
#define fi first
#define se second

#ifdef LOCAL
	#define debug(x) cout << #x << " = " << x << "\n";
#else
	#define debug(x) ;
#endif

template <class A, class B>
ostream& operator << (ostream& out, pair<A, B> x)
{ out << "(" << x.first << ", " << x.second << ")"; return out; }

template <class T>
ostream& operator << (ostream& out, vector<T> x){
	out << "[";
	for (int i=0; i<sz(x); i++) { out << (i ? ", " : "") << x[i]; }
	out << "]"; return out;
}

template <class T>
istream& operator >> (istream& in, vector<T> &x){
	for (auto &i: x) in >> i;
	return in;
}

const ld PI = acos(-1.0);
const int allmod[3] = {(int)1e9+7, 998244353, (int)1e9+9};
const int mod = allmod[0];
const int maxn = 2e5 + 64;
const ll inf = 1e18;
const ld eps = 1e-6;
const int multitest = 0;

int n, m, root = -1;
vi deg, change, res;
vi pt_order, edge_order;
vii edges;
vvii adj;

void dfs(int x, int p = -1){
	if (x == root && p >= 0) return;
	pt_order.pb(x);

	for (auto k: adj[x]){
		if (k.fi == p) continue;
		if (!deg[k.fi]) continue;
		edge_order.pb(k.se);
		dfs(k.fi, x);
		break;
	}
}

void main_program(){
	cin >> n >> m;

	deg.assign(n, 0); change.resize(n); cin >> change;
	adj.resize(n);
	res.resize(m); edges.resize(m);

	for (int i = 0; i < m; i++){
		int x, y; cin >> x >> y;
		x--; y--;
		deg[x]++; deg[y]++;
		edges[i] = {x, y};
		adj[x].pb({y, i}); adj[y].pb({x, i});
	}

	queue<int> q;
	for (int i = 0; i < n; i++){
		if (deg[i] == 1) q.push(i);
	}

	int r = 0;

	while (!q.empty()){
		int x = q.front(); q.pop();
		for (auto k: adj[x]){
			if (deg[k.fi]){
				res[k.se] += change[x] * 2;
				change[k.fi] -= change[x];
				deg[k.fi]--;

				if (deg[k.fi] == 1) q.push(k.fi);
			}
		}
		change[x] = 0;
		if (deg[x]) deg[x]--;
		r++;
	}

	if ((n == m && ((n - r) & 1)) || (*max_element(all(deg)) == 0)){
		for (int i = 0; i < n; i++){
			if (deg[i] > 0) root = i;
		}

		if (root >= 0){
			dfs(root);

			for (auto i: pt_order){
				deg[i] = 0;
			}

			int tt = 0;
			for (auto i: pt_order) tt += change[i];

			for (int i = 1; i < sz(pt_order); i += 2) tt -= change[pt_order[i]] * 2;

			res[edge_order.back()] = tt;
			for (int i = sz(pt_order) - 1; i >= 1; i--){
				res[edge_order[i-1]] = 2 * change[pt_order[i]] - res[edge_order[i]];
			}
		}

		for (int i = 0; i < m; i++) cout << res[i] << "\n";
	}
	else cout << "0\n";
}

void pre_main(){

}

signed main(){
	#ifdef LOCAL
		auto stime = chrono::high_resolution_clock::now();
	#endif
	ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
	#ifndef ONLINE_JUDGE
		if (fopen(".inp", "r")){
			freopen(".inp", "r", stdin);
			freopen(".out", "w", stdout);
		}
	#endif
	int t = 1; if (multitest) cin >> t;
	pre_main();
	while (t--) main_program();
	#ifdef LOCAL
		auto etime = chrono::high_resolution_clock::now();
		auto duration = chrono::duration_cast<chrono::milliseconds>(etime-stime).count();
		cout << "\n[" << duration << "ms]\n";
	#endif
}

Compilation message (stderr)

pipes.cpp: In function 'int main()':
pipes.cpp:154:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  154 |    freopen(".inp", "r", stdin);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~
pipes.cpp:155:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  155 |    freopen(".out", "w", stdout);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~

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