Submission #944078

#	Time	Username	Problem	Language	Result	Execution time	Memory
944078		12345678	Index (COCI21_index)	C++17	110 / 110	394 ms	137372 KiB

index

#include <bits/stdc++.h>

using namespace std;

const int nx=2e5+5;

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

struct persist
{
    struct node
    {
        int vl;
        node *l, *r;
        node(): vl(0), l(0), r(0){}
        node(int vl): vl(vl), 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->vl++, 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->vl=k->l->vl+k->r->vl;
    }
    void show(int l, int r, pnode k)
    {
        cout<<l<<' '<<r<<' '<<k->vl<<'\n';
        if (l==r) return;
        int md=(l+r)/2;
        show(l, md, k->l);
        show(md+1, r ,k->r);
    }
    int query(int l, int r, pnode t, pnode k, int sm)
    {
        if (l==r) return l;
        //cout<<"query "<<l<<' '<<r<<' '<<sm<<' '<<(k->r->vl)-(t->r->vl)<<'\n';
        int md=(l+r)/2;
        if ((k->r->vl)-(t->r->vl)+sm>=md+1) return query(md+1, r, t->r, k->r, sm);
        else return query(l, md, t->l, k->l, (k->r->vl)-(t->r->vl)+sm);
    }
} s;

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

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