Submission #550370

#	Time	Username	Problem	Language	Result	Execution time	Memory
550370		Killer2501	Rainforest Jumps (APIO21_jumps)	C++14	100 / 100	1173 ms	50540 KiB

jumps

#include "jumps.h"
#include<bits/stdc++.h>
using namespace std;
const int N = 2e5+5;
int L[N][20], R[N][20], P[N][20], a[N];
void init(int n, vector<int> A)
{
    for(int i = 1; i <= n; i ++)a[i] = A[i-1];
    stack<int> st;
    for(int i = 1; i <= n; i ++)
    {
        while(!st.empty() && a[i] > a[st.top()])st.pop();
        L[i][0] = st.empty() ? 0 : st.top();
        st.push(i);
    }
    while(!st.empty())st.pop();
    for(int i = n; i > 0; i --)
    {
        while(!st.empty() && a[i] > a[st.top()])st.pop();
        R[i][0] = st.empty() ? n+1 : st.top();
        P[i][0] = (a[L[i][0]] < a[R[i][0]] ? R[i][0] : L[i][0]);
        st.push(i);
    }
    //for(int i = 1; i <= n; i ++)cout << L[i][0] <<" "<<R[i][0] <<" "<<P[i][0] << '\n';
    for(int j = 1; j <= 18; j ++)
    {
        for(int i = 1; i <= n; i ++)
        {
            L[i][j] = L[L[i][j-1]][j-1];
            if(R[i][j-1] == n+1)R[i][j] = n+1;
            else R[i][j] = R[R[i][j-1]][j-1];
            P[i][j] = P[P[i][j-1]][j-1];
 
        }
    }
}
int minimum_jumps(int A, int B, int C, int D)
{
    ++A, ++B, ++C, ++D;
    int pos = B, res = 0;
    for(int j = 18; j >= 0; j --)
    {
        if(L[pos][j] >= A && R[L[pos][j]][0] <= D)pos = L[pos][j];
    }
    for(int j = 18; j >= 0; j --)
    {
        if(P[pos][j] && R[P[pos][j]][0] < C)
        {
            pos = P[pos][j];
            res += (1<<j);
        }
    }
    if(R[pos][0] < C && R[P[pos][0]][0] <= D)
    {
        ++res;
        pos = P[pos][0];
    }
    //cout << pos <<" "<<res<<" ";
    for(int j = 18; j >= 0; j --)
    {
        if(R[pos][j] < C)
        {
            pos = R[pos][j];
            res += (1<<j);
        }
    }
    if(R[pos][0] > D)return -1;
    return res+1;
}

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