Submission #1213384

#	Time	Username	Problem	Language	Result	Execution time	Memory
1213384		ttamx	Exam (eJOI20_exam)	C++20	36 / 100	58 ms	7224 KiB

exam

#include<bits/stdc++.h>

using namespace std;

const int N=100005;

int n;
int a[N],b[N],l[N],r[N];
map<int,int> pos;

struct Fenwick{
    int t[N];
    void update(int i,int v){
        for(;i<=n;i+=i&-i)t[i]=max(t[i],v);
    }
    int query(int i){
        int res=0;
        for(;i>0;i-=i&-i)res=max(res,t[i]);
        return res;
    }
}f;

int main(){
    cin.tie(nullptr)->sync_with_stdio(false);
    cin >> n;
    for(int i=1;i<=n;i++){
        cin >> a[i];
        pos[a[i]]=i;
    }
    for(int i=1;i<=n;i++){
        cin >> b[i];
        if(b[i]<a[i])b[i]=0;
    }
    a[0]=a[n+1]=INT_MAX;
    {
        vector<int> s{0};
        for(int i=1;i<=n;i++){
            while(a[s.back()]<=a[i])s.pop_back();
            l[i]=s.back();
            s.emplace_back(i);
        }
    }
    {
        vector<int> s{n+1};
        for(int i=n;i>=1;i--){
            while(a[s.back()]<=a[i])s.pop_back();
            r[i]=s.back();
            s.emplace_back(i);
        }
    }
    for(int i=1;i<=n;i++){
        int p=pos[b[i]];
        if(p&&l[p]<i&&i<r[p])f.update(p,f.query(p)+1);
    }
    cout << f.query(n);
}

• Subtask 1: 0 / 14
• Subtask 2: 0 / 12
• Subtask 3: 13 / 13
• Subtask 4: 23 / 23
• Subtask 5: 0 / 16
• Subtask 6: 0 / 22