Submission #873928

#	Time	Username	Problem	Language	Result	Execution time	Memory
873928		noiaint	Airplane (NOI23_airplane)	C++17	100 / 100	328 ms	44228 KiB

Main

#include <bits/stdc++.h>

using namespace std;

#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()

#define getbit(x, i) (((x) >> (i)) & 1)
#define bit(x) (1 << (x))
#define popcount __builtin_popcountll

mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
long long rand(long long l, long long r) {
    return l + rd() % (r - l + 1);
}

const int N = 1e6 + 5;
const int mod = 1e9 + 7; // 998244353;
const int lg = 25; // lg + 1
const int inf = 1e9; // INT_MAX;
const long long llinf = 1e18; // LLONG_MAX;

template<class X, class Y>
bool minimize(X &a, Y b) {
    return a > b ? (a = b, true) : false;
}

template<class X, class Y>
bool maximize(X &a, Y b) {
    return a < b ? (a = b, true) : false;
}

template<class X, class Y>
bool add(X &a, Y b) {
    a += b;
    while (a >= mod) a -= mod;
    while (a < 0) a += mod;
    return true;
}

int n, m;
int h[N];
vector<int> adj[N];
vector<int> disS, disE;

void dijkstra(int s, vector<int> &dis) {
    dis.assign(n + 5, inf);
    vector<int> vis(n + 5, 0);
    priority_queue<pair<int, int>, vector<pair<int, int> >, greater<pair<int, int> > > q;
    dis[s] = 0;
    q.emplace(0, s);
    while (q.size()) {
        int du, u;
        tie(du, u) = q.top(); q.pop();
        // if (du > u) continue;
        if (vis[u]) continue;
        vis[u] = true;
        for (int v : adj[u]) {
            if (max(h[v], dis[u] + 1) < dis[v]) {
                dis[v] = max(h[v], dis[u] + 1);
                q.emplace(dis[v], v);
            }
        }
    }
}

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

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

    dijkstra(1, disS);
    dijkstra(n, disE);

    int ans = inf;
    for (int u = 1; u <= n; ++u) {
        ans = min(ans, max(disS[u], disE[u]) * 2);
        for (int v : adj[u]) {
            ans = min(ans, max(disS[u], disE[v]) * 2 + 1);
            ans = min(ans, max(disS[v], disE[u]) * 2 + 1);
        }
    }

    cout << ans;

    return 0;
}

/*

*/

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