제출 #255588

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
255588		amoo_safar	Pipes (BOI13_pipes)	C++17	100 / 100	329 ms	36032 KiB

pipes

// Zende bad Shoma nasime faghat !
#include <bits/stdc++.h>

#define pb push_back
#define F first
#define S second
#define all(x) x.begin(), x.end()
#define debug(x) cerr << #x << " : " << x << '\n'

using namespace std;

typedef long long ll;
typedef long double ld;
typedef string str;
typedef pair<ll, ll> pll;

const ll Mod = 1000000007LL;
const int N = 2e5 + 10;
const ll Inf = 2242545357980376863LL;
const ll Log = 30;

ll n, m, c[N], ans[N];
vector<pll> G[N];

int mk[N];

void Solve(int u){
	mk[u] = 1;
	for(auto [adj, id] : G[u]){
		if(!mk[adj]){
			Solve(adj);
			ans[id] = 2 * c[adj];
			c[u] -= c[adj];
		}
	}
}

ll dep[N];
vector<int> vis, C;

void Find(int u, int p, int d){
	mk[u] = 1;
	dep[u] = d;
	vis.pb(u);
	for(auto [adj, id] : G[u]){
		if(adj == p) continue;
		if(mk[adj]){
			for(int i = dep[adj]; i <= dep[u]; i++) C.pb(vis[i]);
		} else Find(adj, u, d + 1);
	}
	vis.pop_back();
}

int main(){
	ios::sync_with_stdio(0); cin.tie(0); cout.tie(0);

	cin >> n >> m;
	if(m > n) return cout << "0\n", 0;
	for(int i = 1; i <= n; i++) cin >> c[i];

	ll u, v;
	map<pll, int> mp;
	for(int i = 1; i <= m; i++){
		cin >> u >> v;
		G[u].pb({v, i});
		G[v].pb({u, i});
		mp[{u, v}] = i;
		mp[{v, u}] = i;
	}
	if(m == n - 1){
		Solve(1);
	} else {
		Find(1, 0, 0);
		if(C.size() % 2 == 0) return cout << "0\n", 0;
		memset(mk, 0, sizeof mk);
		for(auto x : C) mk[x] = 1;
		for(auto x : C) Solve(x);
		ll a = 1, b = 0;
		for(auto x : C){
			b = c[x] - b;
			a = -a;
		}
		if(b % 2 != 0) assert(false);
		ll X = b / 2;
		ans[mp[ {C[0], C.back() } ]] = 2 * X;
		a = 1, b = 0;
		for(int i = 0; i + 1 < C.size(); i++){
			ll x = C[i];
			b = c[x] - b;
			a = -a;
			ans[ mp[{C[i], C[i + 1]}] ] = 2 * (a * X + b);
		}
	}

	for(int i = 1; i <= m; i++) cout << ans[i] << '\n';
	return 0;
}

/*
4 4
2 6 10 0
1 2
2 3
3 1
4 2

*/

컴파일 시 표준 에러 (stderr) 메시지

pipes.cpp: In function 'void Find(int, int, int)':
pipes.cpp:45:19: warning: unused variable 'id' [-Wunused-variable]
  for(auto [adj, id] : G[u]){
                   ^
pipes.cpp: In function 'int main()':
pipes.cpp:87:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i + 1 < C.size(); i++){
                  ~~~~~~^~~~~~~~~~

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