Submission #1102408

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102408		tuannm	Airplane (NOI23_airplane)	C++17	100 / 100	271 ms	20676 KiB

Main

#include<bits/stdc++.h>
#define ii pair<int, int>
#define ll pair<long long, long long>
#define fi first
#define se second
#define pb push_back
using namespace std;
const int mod[2] = {1000000007, 998244353};
const int N = 2e5 + 1;
const string NAME = "";
int n, m, a[N];
long long d[2][N];
vector<int> adj[N];

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

    for(int i = 1; i <= n; ++i)
        cin >> a[i];

    for(int i = 1; i <= m; ++i){
        int u, v;
        cin >> u >> v;

        adj[u].pb(v);
        adj[v].pb(u);
    }
}

void solve(){
    priority_queue<pair<long long, int>> pq;
    for(int i = 1; i <= n; ++i)
        d[0][i] = d[1][i] = 1e16;

    d[0][1] = d[1][n] = 0;

    pq.push({0, 1});
    while(!pq.empty()){
        auto [dis, u] = pq.top();
        pq.pop();
        dis = -dis;

        if(dis != d[0][u])
            continue;

        for(int v : adj[u]){
            if(d[0][v] > max(d[0][u] + 1, 1LL * a[v])){
                d[0][v] = max(d[0][u] + 1, 1LL * a[v]);
                pq.push({-d[0][v], v});
            }
        }
    }

    pq.push({0, n});
    while(!pq.empty()){
        auto [dis, u] = pq.top();
        pq.pop();
        dis = -dis;

        if(dis != d[1][u])
            continue;

        for(int v : adj[u]){
            if(d[1][v] > max(d[1][u] + 1, 1LL * a[v])){
                d[1][v] = max(d[1][u] + 1, 1LL * a[v]);
                pq.push({-d[1][v], v});
            }
        }
    }

    long long ans = 1e16;

    for(int u = 1; u <= n; ++u){
        ans = min(ans, max(d[0][u], d[1][u]) * 2LL);

        for(int v : adj[u])
            ans = min(ans, max(d[0][u], d[1][v]) * 2LL + 1LL);
    }

    cout << ans;
}

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

    if(fopen((NAME + ".inp").c_str(), "r")){
        freopen((NAME + ".inp").c_str(), "r", stdin);
        freopen((NAME + ".out").c_str(), "w", stdout);
    }

    inp();
    solve();
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:89:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   89 |         freopen((NAME + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:90:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   90 |         freopen((NAME + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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