Submission #1122619

#	Time	Username	Problem	Language	Result	Execution time	Memory
1122619		nhphuc	Curtains (NOI23_curtains)	C++17	100 / 100	1081 ms	75052 KiB

curtains

#include <bits/stdc++.h>
using namespace std;

const int N = 500500;

int n, m, q, t[N * 4], lz[N * 4];
string ans[N];
vector<int> adj[N];
vector<pair<int, int>> que[N];

void push (int id, int l, int r){
    if (l == r){
        return;
    }
    for (int i = id * 2; i <= id * 2 + 1; ++i){
        t[i] = max(t[i], lz[id]);
        lz[i] = max(lz[i], lz[id]);
    }
    return;
}

void upd (int id, int l, int r, int u, int v, int x){
    push(id, l, r);
    if (l > v || r < u){
        return;
    }
    if (l >= u && r <= v){
        t[id] = max(t[id], x);
        lz[id] = max(lz[id], x);
        return;
    }
    int m = l + r >> 1;
    upd(id * 2, l, m, u, v, x);
    upd(id * 2 + 1, m + 1, r, u, v, x);
    t[id] = min(t[id * 2], t[id * 2 + 1]);
    return;
}

int get (int id, int l, int r, int u, int v){
    push(id, l, r);
    if (l > v || r < u){
        return n;
    }
    if (l >= u && r <= v){
        return t[id];
    }
    int m = l + r >> 1;
    return min(get(id * 2, l, m, u, v), get(id * 2 + 1, m + 1, r, u, v));
}

int32_t main (){
    ios::sync_with_stdio(false); cin.tie(nullptr);
    if (fopen("test.inp", "r")){
        freopen("test.inp", "r", stdin);
        freopen("test.out", "w", stdout);
    }
    cin >> n >> m >> q;
    for (int i = 1; i <= m; ++i){
        int l, r; cin >> l >> r;
        adj[r].push_back(l);
    }
    for (int i = 1; i <= q; ++i){
        int l, r; cin >> l >> r;
        que[r].push_back({l, i});
    }
    for (int i = 1; i <= n; ++i){
        for (int l : adj[i]){
            upd(1, 1, n, l, i, l);
        }
        for (auto [l, j] : que[i]){
            ans[j] = (get(1, 1, n, l, i) == l ? "YES" : "NO");
        }
    }
    for (int i = 1; i <= q; ++i){
        cout << ans[i] << "\n";
    }
}

Compilation message (stderr)

curtains.cpp: In function 'int32_t main()':
curtains.cpp:54:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   54 |         freopen("test.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
curtains.cpp:55:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |         freopen("test.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 3 / 3
• Subtask 2: 6 / 6
• Subtask 3: 15 / 15
• Subtask 4: 20 / 20
• Subtask 5: 36 / 36
• Subtask 6: 20 / 20