Submission #1079464

#	Time	Username	Problem	Language	Result	Execution time	Memory
1079464		12345678	Index (COCI21_index)	C++17	110 / 110	370 ms	137236 KiB

index

#include <bits/stdc++.h>

using namespace std;

const int nx=2e5+5;

int n, q, p[nx], l, r;

struct persistsegtree
{
    struct node
    {
        int sm;
        node *l, *r;
        node(int sm): sm(sm), l(0), r(0){}
    };
    typedef node* pnode;
    pnode rt[nx];
    void build(int l, int r, pnode &k)
    {
        k=new node(0);
        if (l==r) return;
        int md=(l+r)/2;
        build(l, md, k->l);
        build(md+1, r, k->r);
    }
    void update(int l, int r, pnode &k, pnode t, int idx)
    {
        k=new node(*t);
        if (l==r) return k->sm++, void();
        int md=(l+r)/2;
        if (idx<=md) update(l, md, k->l, t->l, idx);
        else update(md+1, r, k->r, t->r, idx);
        k->sm=k->l->sm+k->r->sm;
    }
    int query(int l, int r, pnode k, pnode t, int sv)
    {
        if (l==r) return l;
        int md=(l+r)/2;
        if (k->r->sm-t->r->sm+sv>=md+1) return query(md+1, r, k->r, t->r, sv);
        else return query(l, md, k->l, t->l, sv+k->r->sm-t->r->sm);
    }
} s;

int main()
{
    cin.tie(NULL)->sync_with_stdio(false);
    cin>>n>>q;
    s.build(1, n, s.rt[0]);
    for (int i=1; i<=n; i++) cin>>p[i], p[i]=min(p[i], n), s.update(1, n, s.rt[i], s.rt[i-1], p[i]);
    while (q--) cin>>l>>r, cout<<s.query(1, n, s.rt[r], s.rt[l-1], 0)<<'\n';
} 

• Subtask 1: 20 / 20
• Subtask 2: 40 / 40
• Subtask 3: 50 / 50