Submission #824278

#	Time	Username	Problem	Language	Result	Execution time	Memory
824278		Dec0Dedd	Global Warming (CEOI18_glo)	C++14	100 / 100	518 ms	58716 KiB

glo

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

#pragma GCC optimize("Ofast")
 
const int N = 2e5+10;
 
struct segtree {
    vector<int> t;
    int sz;
 
    void init(int k) {
        sz=1;
        while (sz < 4*k) sz*=2;
        t.resize(sz+1);
    }
 
    void upd(int v, int l, int r, int p, int val) {
        if (l == r) {
            t[v]=max(t[v], val);
            return;
        } int m=(l+r)/2;
        if (p <= m) upd(2*v, l, m, p, val);
        else upd(2*v+1, m+1, r, p, val);
        t[v]=max(t[2*v], t[2*v+1]);
    }
 
    int que(int v, int l, int r, int ql, int qr) {
        if (l > qr || r < ql) return 0;
        if (l >= ql && r <= qr) return t[v];
        int m=(l+r)/2;
        return max(que(2*v, l, m, ql, qr), que(2*v+1, m+1, r, ql, qr));
    }
};
 
int a[N], b[N], n, x, pre[N], suf[N];
unordered_map<int, int> sc;
 
int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(NULL);
    cout.tie(NULL);
    
    cin>>n>>x;
 
    set<int> st;
    for (int i=1; i<=n; ++i) {
        cin>>a[i];
        st.insert(a[i]), st.insert(a[i]+x);
    }
 
    int i=1;
    for (auto u : st) sc[u]=i++;

    for (int i=1; i<=n; ++i) b[i]=sc[a[i]];
 
    segtree tr2; tr2.init(2*n+10);
    for (int i=n; i>=1; --i) {
        suf[i]=tr2.que(1, 1, 2*n, b[i]+1, 2*n)+1;
        tr2.upd(1, 1, 2*n, b[i], suf[i]);
    }
 
    /*
    cout<<"pre: ";
    for (int i=1; i<=n; ++i) cout<<pre[i]<<" ";
    cout<<"\n";
 
    cout<<"suf: ";
    for (int i=1; i<=n; ++i) cout<<suf[i]<<" ";
    cout<<"\n";
    */
 
    int ans=0;
    segtree tr; tr.init(2*n+1);
    for (int i=1; i+1<=n; ++i) {
        pre[i]=tr.que(1, 1, 2*n, 1, b[i]-1)+1;
        tr.upd(1, 1, 2*n, b[i], pre[i]);
        ans=max(ans, tr.que(1, 1, 2*n, 1, sc[a[i+1]+x]-1)+suf[i+1]);
    } cout<<ans<<"\n";
}

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 25 / 25