Submission #1104962

#	Time	Username	Problem	Language	Result	Execution time	Memory
1104962		ro9669	Airplane (NOI23_airplane)	C++17	100 / 100	267 ms	31952 KiB

Main

#include <bits/stdc++.h>
#define fi first
#define se second
#define all(v) v.begin() , v.end()
#define sz(v) int(v.size())
#define unq(v) sort(all(v)); v.resize(unique(all(v)) - v.begin());
using namespace std;

typedef long long ll;
typedef pair<int , int> ii;
typedef pair<long long , int> lli;

const int maxN = int(2e5)+7;
const int maxM = int(4e5)+7;
const ll inf = ll(1e18)+7;

int n , m , a[maxN];
ii E[maxM];
vector<int> g[maxN];

namespace sub1{
    bool check(){
        if (m != n - 1) return 0;
        for (int i = 1 ; i <= m ; i++){
            if (E[i].fi != i || E[i].se != i + 1) return 0;
        }
        return 1;
    }

    void solve(){
        int p = -1;
        for (int i = 1 ; i <= n ; i++){
            if (p == -1 || a[p] < a[i]) p = i;
        }
        ll ans = 0;
        int pre = 0 , suf = 0;
        for (int i = 2 ; i <= p ; i++){
            if (pre == a[p]){
                ans++;
            }
            else{
                ans += 1ll * max(a[i] - pre , 1);
                pre = max(pre + 1 , a[i]);
            }
        }
        for (int i = n - 1 ; i >= p ; i--){
            if (suf == a[p]){
                ans++;
            }
            else{
                ans += 1ll * max(a[i] - suf , 1);
                suf = max(suf + 1 , a[i]);
            }
        }
        cout << ans << "\n";
    }
}

namespace sub2{
    ll d[2][maxN];
    int h[2][maxN];

    void dijkstra(int id , int st){
        for (int i = 1 ; i <= n ; i++){
            d[id][i] = inf;
            h[id][i] = INT_MAX;
        }
        d[id][st] = 0;
        h[id][st] = 0;
        priority_queue<lli , vector<lli> , greater<lli>> pq;
        pq.push({d[id][st] , st});
        while (pq.empty() == 0){
            auto it = pq.top(); pq.pop();
            int u = it.se;
            if (it.fi != d[id][u]) continue;
            for (int v : g[u]){
                int w = max(a[v] - h[id][u] , 1);
                if (d[id][v] == d[id][u] + 1ll * w){
                    h[id][v] = min(h[id][v] , max(a[v] , h[id][u] + 1));
                }
                if (d[id][v] > d[id][u] + 1ll * w){
                    d[id][v] = d[id][u] + 1ll * w;
                    h[id][v] = max(a[v] , h[id][u] + 1);
                    pq.push({d[id][v] , v});
                }
            }
        }
    }

    void solve(){
        dijkstra(0 , 1);
        dijkstra(1 , n);
        ll ans = inf;
        for (int i = 1 ; i <= n ; i++){
            if (h[0][i] == h[1][i]){
                ans = min(ans , d[0][i] + d[1][i]);
            }
            for (int j : g[i]){
                if (h[0][i] == h[1][j]){
                    ans = min(ans , d[0][i] + d[1][j] + 1ll);
                }
            }
        }
        cout << ans << "\n";
    }
}

void solve(){
    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;
        E[i] = {u , v};
        g[u].push_back(v);
        g[v].push_back(u);
    }
    //if (sub1::check()) return sub1::solve();
    return sub2::solve();
}

#define name "A"

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    if (fopen(name".INP" , "r")){
        freopen(name".INP" , "r" , stdin);
        freopen(name".OUT" , "w" , stdout);
    }
    int t = 1; //cin >> t;
    while (t--) solve();
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:127:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  127 |         freopen(name".INP" , "r" , stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:128:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |         freopen(name".OUT" , "w" , stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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