Submission #1102370

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102370		thangdz2k7	Airplane (NOI23_airplane)	C++17	0 / 100	3 ms	6480 KiB

Main

// author : thembululquaUwU
// 3.9.2024

#include <bits/stdc++.h>

using namespace std;

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

template <class A, class B>
bool minl(A &a, B &b){
    return a > b ? (a = b), true : false;
}

int n, a[N];
vector <int> adj[N];

void dijkstra(int src, int d[]){
    fill(d + 1, d + n + 1, mod);
    using T = pair <int, int>;
    priority_queue <T, vector <T>, greater <T>> qu;
    d[src] = 0; qu.emplace(0, src);
    while (qu.size()){
        auto [du, u] = qu.top(); qu.pop();
        if (d[u] != du) continue;
        for (int v : adj[u]){
            if (minl(d[v], max(d[u] + 1, a[v]))){
                qu.emplace(d[v], v);
            }
        }
    }
}

int m, up[N], down[N];

void solve(){
    cin >> n >> m;
    for (int i = 1; i <= n; ++ i) cin >> a[i];
    for (int i = 1, u, v; i <= m; ++ i){
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    dijkstra(1, up);
    dijkstra(n, down);
    int res = mod;
    for (int i = 1; i <= n; ++ i) {
        res = min(res, up[i] + down[i]);
        for (int j : adj[i]) res = min(res, max(up[i], down[j]) * 2 + 1);
    }

    cout << res;
}

int main(){
    if (fopen("pqh.inp", "r")){
        freopen("pqh.inp", "r", stdin);
        freopen("pqh.out", "w", stdout);
    }
    ios_base::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);

    int t = 1; // cin >> t;
    while (t --) solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:59:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   59 |         freopen("pqh.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:60:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   60 |         freopen("pqh.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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