Submission #1124396

#	Time	Username	Problem	Language	Result	Execution time	Memory
1124396		tuannm	Curtains (NOI23_curtains)	C++20	0 / 100	18 ms	23880 KiB

curtains

#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 = 5e5 + 1;
const string NAME = "";
int n, m, q;
vector<int> lft[N];
vector<ii> queries[N];
bool ans[N];

struct SegTree{
    int n, h;
    vector<int> tree, lazy;

    SegTree(int _n) : n(_n){
        tree.resize(2 * n);
        lazy.resize(n);
        h = sizeof(int) * 8 - __builtin_clz(n);
    }

    void build(){
        for(int i = 0; i < 2 * n; ++i)
            tree[i] = 0;

        for(int i = 0; i < n; ++i)
            lazy[i] = 0;
    }

    void up(int u){
        while(u > 1)
            u >>= 1, tree[u] = min(max(lazy[u], tree[u << 1]), max(lazy[u], tree[u << 1 | 1]));
    }

    void apply(int u, int val){
        tree[u] = max(tree[u], val);
        if(u < n)
            lazy[u] = max(lazy[u], val);
    }

    void down(int u){
        for(int s = h; s; --s){
            int i = u >> s;

            if(lazy[i]){
              apply(i << 1, lazy[i]);
              apply(i << 1 | 1, lazy[i]);
              lazy[i] = 0;
            }
        }
    }

    void update(int l, int r, int val){
        --l;
        l += n, r += n;
        int l0 = l, r0 = r;

        for(; l < r; l >>= 1, r >>= 1){
            if(l & 1)
                apply(l++, val);
            if(r & 1)
                apply(--r, val);
        }

        up(l0);
        up(r0 - 1);
    }

    int query(int l, int r){
        l += n, r += n;
        down(l);
        down(r - 1);

        int res = 2e9;

        for(; l < r; l >>= 1, r >>= 1){
            if(l & 1)
                res = min(res, tree[l++]);
            if(r & 1)
                res = min(tree[--r], res);
        }
        return res;
    }
};

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

    for(int i = 1; i <= m; ++i){
        int l, r;
        cin >> l >> r;
        lft[r].pb(l);
    }

    for(int i = 1; i <= q; ++i){
        int s, t;
        cin >> s >> t;

        queries[t].pb({s, i});
    }
}

void solve(){
    SegTree st(n);

    for(int r = 1; r <= n; ++r){
        for(int l : lft[r])
            st.update(l, r, l);

        for(auto [l, id] : queries[r])
            ans[id] = (st.query(l, r) == l);
    }

    for(int i = 1; i <= q; ++i)
        cout << (ans[i] ? "YES\n" : "NO\n");
}

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)

curtains.cpp: In function 'int main()':
curtains.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 + ".inp").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
curtains.cpp:129:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |         freopen((NAME + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 3
• Subtask 2: 0 / 6
• Subtask 3: 0 / 15
• Subtask 4: 0 / 20
• Subtask 5: 0 / 36
• Subtask 6: 0 / 20