Submission #985921

#	Time	Username	Problem	Language	Result	Execution time	Memory
985921		phoenix	Rainforest Jumps (APIO21_jumps)	C++17	44 / 100	857 ms	46444 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>

using namespace std;

const int N = 200200;

int B[N][18];
int L[N][18];
int R[N][18];


void init(int n, vector<int> H) {
    L[n][0] = R[n][0] = n;
    H.push_back(1e9 + 10);

    vector<int> stack;
    for (int i = 0; i < n; i++) {
        while (!stack.empty() && H[stack.back()] < H[i]) 
            stack.pop_back();
        L[i][0] = (stack.empty() ? n : stack.back());
        stack.push_back(i);
    }
    stack.clear();
    for (int i = n - 1; i >= 0; i--) {
        while (!stack.empty() && H[stack.back()] < H[i])
            stack.pop_back();
        R[i][0] = (stack.empty() ? n : stack.back());
        stack.push_back(i);
    }
    stack.clear();
    for (int i = 0; i <= n; i++) {
        B[i][0] = (H[L[i][0]] < H[R[i][0]] ? R[i][0] : L[i][0]);
    }
    // for (int i = 0; i < n; i++)
    //     cout << L[i][0] << ' ';
    // cout << '\n';
    // for (int i = 0; i < n; i++)
    //     cout << R[i][0] << ' ';
    // cout << '\n';
    // cout << '\n';

    for (int k = 1; k < 18; k++) {
        for (int i = 0; i <= n; i++) {
            L[i][k] = L[L[i][k - 1]][k - 1];
            R[i][k] = R[R[i][k - 1]][k - 1];
            B[i][k] = B[B[i][k - 1]][k - 1];
        }
    }
}   

int minimum_jumps(int l, int r, int c, int d) {
    int ans = 0;
    for (int k = 17; k >= 0; k--) {
        if (L[r][k] >= l && R[L[r][k]][0] <= d) 
            r = L[r][k];
    }
    for (int k = 17; k >= 0; k--) {
        if (r < c && R[B[r][k]][0] <= d) {
            r = B[r][k];
            ans += (1 << k);
        } 
    }                            
    for (int k = 17; k >= 0; k--) {
        if (r < c && R[r][k] <= d) {
            r = R[r][k];
            ans += (1 << k);
        }
    }
    if (c <= r && r <= d) return ans;
    return -1;
}

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