| # | Time | Username | Problem | Language | Result | Execution time | Memory | 
|---|---|---|---|---|---|---|---|
| 1054049 | Kerim | Rainforest Jumps (APIO21_jumps) | C++17 | 0 ms | 0 KiB | 
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
constexpr int kMaxLogN = 20;
int N;
vector<int> H;
vector<vector<int>> L, R;
vector<vector<int>> higher;
void init(int _N, std::vector<int> _H) {
  N = _N;
  H = _H;
  H.insert(H.begin(), INT_MAX);
  H.insert(H.end(), INT_MAX);
  N += 2;
  L = R = higher = vector<vector<int>>(kMaxLogN, vector<int>(N));
  stack<int> decreasing_height;
  for (int i = 0; i < N; ++i) {
    while (!decreasing_height.empty() && H[decreasing_height.top()] <= H[i]) {
      decreasing_height.pop();
    }
    L[0][i] = decreasing_height.empty() ? i : decreasing_height.top();
    decreasing_height.push(i);
  }
  while (!decreasing_height.empty()) {
    decreasing_height.pop();
  }
  for (int i = N - 1; i >= 0; --i) {
    while (!decreasing_height.empty() && H[decreasing_height.top()] <= H[i]) {
      decreasing_height.pop();
    }
    R[0][i] = decreasing_height.empty() ? i : decreasing_height.top();
    decreasing_height.push(i);
  }
  for (int i = 0; i < N; ++i) {
    higher[0][i] = H[L[0][i]] > H[R[0][i]] ? L[0][i] : R[0][i];
  }
  for (int j = 1; j < kMaxLogN; ++j) {
    for (int i = 0; i < N; ++i) {
      L[j][i] = L[j - 1][L[j - 1][i]];
      R[j][i] = R[j - 1][R[j - 1][i]];
      higher[j][i] = higher[j - 1][higher[j - 1][i]];
    }
  }
}
int minimum_jumps(int s, int e) {
  int jumps = 0;
  for (int j = kMaxLogN - 1; j >= 0; --j) {
    if (H[higher[j][s]] <= H[e]) {
      s = higher[j][s];
      jumps |= (1 << j);
    }
  }
  if (H[L[0][s]] > H[e]) {
    for (int j = kMaxLogN - 1; j >= 0; --j) {
      if (H[R[j][s]] <= H[e]) {
        s = R[j][s];
        jumps += (1 << j);
      }
    }
  } else {
    for (int j = kMaxLogN - 1; j >= 0; --j) {
      if (H[L[j][s]] <= H[e]) {
        s = L[j][s];
        jumps += (1 << j);
      }
    }
  }
  return s == e ? jumps : -1;
}
int minimum_jumps(int A, int B, int C, int D) {
  ++A; ++B; ++C; ++D;
  int s = B;
  return minimum_jumps(s, e);
}
// int main(){
//     init(3, {2, 1, 3});
//     printf("%d\n", minimum_jumps(0, 1, 2, 2));
// }
