Submission #949670

#	Time	Username	Problem	Language	Result	Execution time	Memory
949670		Aiperiii	Rainforest Jumps (APIO21_jumps)	C++14	0 / 100	151 ms	30884 KiB

jumps

#include <bits/stdc++.h>
#include "jumps.h"
//#define int long long
#define ff first
#define ss second
#define pb push_back
#define all(x) x.begin(),x.end()
using namespace std;
const int N=2e5+5;
int jmp_high[N][20],jmp_low[N][20];
vector <int> h;
int n;
void init(int N,vector<int> H) {
    stack <int> st;
    h.pb(1e9);n=N;
    for(int i=0;i<N;i++)h.pb(H[i]);
    vector <int> l(N+1),r(N+1);
    for(int i=0;i<N;i++){
        while(!st.empty() && H[st.top()]<H[i]){
            r[st.top()+1]=i+1;
            st.pop();
        }
        st.push(i);
    }
    while(!st.empty())st.pop();
    for(int i=N-1;i>=0;i--){
        while(!st.empty() && H[st.top()]<H[i]){
            l[st.top()+1]=i+1;
            st.pop();
        }
        st.push(i);
    }
    /*for(int i=1;i<=N;i++){
        cout<<l[i]<<" ";
    }
    cout<<"\n";
    for(int i=1;i<=N;i++){
        cout<<r[i]<<" ";
    }
    cout<<"\n";*/
    for(int i=1;i<=N;i++){
        if(H[l[i]]>H[r[i]])swap(l[i],r[i]);
        if(l[i] && r[i]){
            jmp_high[i][0]=r[i];
            jmp_low[i][0]=l[i];
        }
        else if(l[i])jmp_high[i][0]=l[i];
        else if(r[i])jmp_high[i][0]=r[i];
    }
    for(int k=1;k<20;k++){
        for(int i=1;i<=N;i++){
            jmp_high[i][k]=jmp_high[jmp_high[i][k-1]][k-1];
            jmp_low[i][k]=jmp_low[jmp_low[i][k-1]][k-1];
        }
    }
}

int minimum_jumps(int A, int B, int C, int D) {
    A++;B++;C++;D++;
    int ans=0;
    for(int k=19;k>=0;k--){
        if(h[jmp_high[A][k]]<=h[C]){
            A=jmp_high[A][k];
            ans+=(1<<k);
        }
    }
    for(int k=19;k>=0;k--){
        if(h[jmp_low[A][k]]<=h[C]){
            A=jmp_low[A][k];
            ans+=(1<<k);
        }
    }
    if(A==C)return ans;
    return -1;
}
/*signed main(){
    ios_base::sync_with_stdio();
    cin.tie(0);cout.tie(0);
    int n,q;
    cin>>n>>q;
    vector <int> a(n);
    for(int i=0;i<n;i++)cin>>a[i];
    init(n,a);
    for(int i=0;i<q;i++){
        int a,b,c,d;
        cin>>a>>b>>c>>d;
        cout<<minimum_jumps(a,b,c,d)<<"\n";
    }
}*/

/*
 
 7 10
 3 2 1 6 4 5 7
 
 */

• Subtask 1: 0 / 4
• Subtask 2: 0 / 8
• Subtask 3: 0 / 13
• Subtask 4: 0 / 12
• Subtask 5: 0 / 23
• Subtask 6: 0 / 21
• Subtask 7: 0 / 19