Submission #1102409

#	Time	Username	Problem	Language	Result	Execution time	Memory
1102409		LTTrungCHL	Airplane (NOI23_airplane)	C++17	100 / 100	410 ms	23228 KiB

Main

///***LTT***///
/// ->NHAT QUOC GIA<- ///
#include<bits/stdc++.h>
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
//#define int long long
#define endl "\n"
#define F first
#define S second
#define pb push_back
using namespace std;
vector <int> lg2;
//void MAKE_LOG_ARR(int n){
//    lg2.resize(n + 3);
//    for (int i = 1;i <= n;++i){
//        lg2[i] = __lg(i);
//    }
//}
const long long oo = 1e9+7;
const int N = 2 * 1e5 + 10;
int n, a[N], m;
vector <int> adj[N];

    priority_queue <pair <long long, int>> pq;
namespace sub2{
    long long dis[N];
    void solve(){
        long long ans = oo * oo;
        for (int i = 1;i <= n;++i){
            for (int j = 1;j <= n;++j){
                dis[j] = oo * oo;
            }
            dis[1] = 0;
            pq.push({0,1});
            while (!pq.empty()){
                int u = pq.top().S;
                long long d = -pq.top().F;
                pq.pop();
                for (int v : adj[u]){
                    if (a[v] > a[i]) continue;
                    int nxt = (d < a[v] ? a[v] : d + 1);
                    if (nxt < dis[v]){
                        dis[v] = nxt;
                        pq.push({-dis[v], v});
                    }
                }
            }
            long long res = dis[i];
            for (int j = 1;j <= n;++j){
                dis[j] = oo * oo;
            }
            dis[n] = 0;
            pq.push({0,n});
            while (!pq.empty()){
                int u = pq.top().S;
                long long d = -pq.top().F;
                pq.pop();
                for (int v : adj[u]){
                    if (a[v] > a[i]) continue;
                    int nxt = (d < a[v] ? a[v] : d + 1);
                    if (nxt < dis[v]){
                        dis[v] = nxt;
                        pq.push({-dis[v], v});
                    }
                }
            }
            res += dis[i];
            ans = min(ans, res);
        }
        cout << ans;
    }
};
namespace sub1{
    long long dis[N], dis2[N];
    void solve(){
        int mx = 1;
        for (int i = 2;i <= n;++i){
            if (a[mx] < a[i]){
                mx = i;
            }
        }
        for (int i = 2;i <= n;++i){
            int nxt = (dis[i - 1] < a[i] ? a[i] : dis[i - 1] + 1);
            dis[i] = nxt;
        }
        for (int i = n - 1;i >= 1;--i){
            int nxt = (dis2[i + 1] < a[i] ? a[i] : dis2[i + 1] + 1);
            dis2[i] = nxt;
        }
        long long ans = oo * oo;
        ans = min(ans, dis[mx] + dis2[mx]);
        cout << ans;
        return;
    }
};
namespace ac{
    long long d1[N], d2[N];
    void solve(){
        for (int i = 1;i <= n;++i){
            d1[i] = oo * oo;
        }
        for (int i = 1;i <= n;++i){
            d2[i] = oo * oo;
        }
        d1[1] = 0;
        d2[n] = 0;
        pq.push({0,1});
        while (!pq.empty()){
            int u = pq.top().S;
            long long d = -pq.top().F;
            pq.pop();
            if (d > d1[u]) continue;
            for (int v : adj[u]){
                int nxt = (d < a[v] ? a[v] : d + 1);
                if (nxt < d1[v]){
                    d1[v] = nxt;
                    pq.push({-d1[v], v});
                }
            }
        }
        pq.push({0,n});
        while (!pq.empty()){
            int u = pq.top().S;
            long long d = -pq.top().F;
            pq.pop();
            if (d > d2[u]) continue;
            for (int v : adj[u]){
                int nxt = (d < a[v] ? a[v] : d + 1);
                if (nxt < d2[v]){
                    d2[v] = nxt;
                    pq.push({-d2[v], v});
                }
            }
        }
        long long ans = oo * oo;
        for (int i = 1;i <= n;++i){
            ans = min(ans, max(d1[i], d2[i]) * 2);
            for (int v : adj[i]){
                ans = min(ans, max(d1[i], d2[v]) * 2 + 1);
            }
        }
        cout << ans;
        return;
    }
};
void solve(){
    cin >> n >> m;
    for (int i = 1;i <= n;++i){
        cin >> a[i];
    }
    bool cksub1 = true;
    for (int i = 1;i <= m;++i){
        int u, v;
        cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
        if (v != u + 1){
            cksub1 = false;
        }
    }
    if (m == n - 1 and cksub1){
        sub1::solve();
        return;
    }
    if (n <= 2000 and m <= 4000){
        sub2::solve();
        return;
    }
    ac::solve();
    return;
}
int main(){
    ios_base::sync_with_stdio(NULL);
    cin.tie(NULL);
    cout.tie(NULL);
    if (fopen("ltt.inp", "r")){
        freopen("ltt.inp", "r", stdin);
        freopen("ltt.out", "w", stdout);
    }
//    int t;
//    cin >> t;
//    while(t--){
    solve();
//    }
    return 0;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:178:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  178 |         freopen("ltt.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
Main.cpp:179:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  179 |         freopen("ltt.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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