Submission #1179316

#	Time	Username	Problem	Language	Result	Execution time	Memory
1179316		tminh	Airplane (NOI23_airplane)	C++20	63 / 100	1097 ms	49588 KiB

Main

/*
	Em la may troi trong gio
	Anh la cay nhieu dan do
*/

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

#define ll long long
#define endl '\n'
#define fi first
#define se second
#define vall(a) (a).begin(), (a).end()
#define sze(a) (int)a.size()
#define pii pair<int, ll>


#define ep emplace_back
#define pb push_back
#define pf push_front


const int mod = 1e9 + 7;
const signed N = 2e5 + 5;
const int oo = 1e9;

int n, m; 
vector<int> adj[N];
pair<int, int> t[N << 1];
int d[N][2], h[N];

void dijkstra(int s, bool type) {
	for (int i = 1; i <= n; ++i) d[i][type] = oo;
	priority_queue<pii, vector<pii>, greater<pii>> q;
	d[s][type] = 0;
	q.push(make_pair(s, d[s][type]));
	
	while(!q.empty()) {
		auto[u, c] = q.top();
		q.pop();
		if (d[u][type] != c) continue;
		
		for (int v : adj[u]) {
			if (d[v][type] > max(h[v], d[u][type] + 1)) {
				d[v][type] = max(h[v], d[u][type] + 1);
				q.push(make_pair(v, d[v][type]));
			}
		}
	}
}

void output() {
	dijkstra(1, 0);
	dijkstra(n, 1);
	int ans = oo;
	for (int i = 1; i <= n; ++i) ans = min(ans, (max(d[i][0], d[i][1]) << 1));
	for (int i = 1; i <= m; ++i) {
		auto [u, v] = t[i];
		ans = min(ans, ((max(d[u][0], d[v][1]) << 1) | 1));
		ans = min(ans, ((max(d[v][0], d[u][1]) << 1) | 1));
	}
	cout << ans;
    return;
}

void input() {
	cin >> n >> m;
	for (int i = 1; i <= n; ++i) cin >> h[i];
	for (int i = 1; i <= m; ++i) {
		cin >> t[i].fi >> t[i].se;
		int u = t[i].fi, v = t[i].se;
		adj[u].pb(v);
		adj[v].pb(u);
	}
    output();
    return;
}

signed main() {
    if(fopen("", "r")) {
        freopen("", "r", stdin);
        freopen("", "w", stdout);
    }
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);

    input();
    cerr << "Time elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << 's' << endl;
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:81:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   81 |         freopen("", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~
Main.cpp:82:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |         freopen("", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 10 / 10
• Subtask 3: 31 / 31
• Subtask 4: 0 / 37