Submission #803996

#	Time	Username	Problem	Language	Result	Execution time	Memory
803996		guagua0407	Cat Exercise (JOI23_ho_t4)	C++17	41 / 100	62 ms	31784 KiB

Main

#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define f first
#define s second
#define all(x) x.begin(),x.end()

const int mxn=2e5+5;
int num[mxn];
pair<int,int> table[20][mxn];

ll cal(int l,int r){
    if(l==r) return 0;
    int p=__lg(r-l+1);
    int node=max(table[p][l],table[p][r+1-(1<<p)]).s;
    int leftnode=-1,rightnode=-1;
    if(node>l){
        p=__lg(node-l);
        leftnode=max(table[p][l],table[p][node-(1<<p)]).s;
    }
    if(node<r){
        p=__lg(r-node);
        rightnode=max(table[p][node+1],table[p][r+1-(1<<p)]).s;
    }
    //cout<<l<<' '<<r<<' '<<leftnode<<' '<<node<<' '<<rightnode<<'\n';
    if(leftnode!=-1 and rightnode!=-1){
        return max(cal(l,node-1)+1ll*(node-leftnode),cal(node+1,r)+1ll*(rightnode-node));
    }
    else if(leftnode!=-1){
        return cal(l,node-1)+1ll*(node-leftnode);
    }
    else{
        return cal(node+1,r)+1ll*(rightnode-node);
    }
}

int main(){
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
    int n;
    cin>>n;
    for(int i=0;i<n;i++){
        cin>>num[i];
        table[0][i]={num[i],i};
        num[i]--;
    }
    for(int i=0;i<n-1;i++){
        int a,b;
        cin>>a>>b;
    }
    for(int i=1;i<20;i++){
        for(int j=0;j+(1<<i)<=n;j++){
            table[i][j]=max(table[i-1][j],table[i-1][j+(1<<(i-1))]);
        }
    }
    cout<<cal(0,n-1)<<'\n';
}

• Subtask 1: 7 / 7
• Subtask 2: 7 / 7
• Subtask 3: 7 / 7
• Subtask 4: 0 / 10
• Subtask 5: 20 / 20
• Subtask 6: 0 / 23
• Subtask 7: 0 / 26