Submission #1101863

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101863		blackslex	Rainforest Jumps (APIO21_jumps)	C++17	27 / 100	953 ms	57540 KiB

jumps

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

using namespace std;
using pii = pair<int, int>;

const int MxN = 2e5 + 5, K = 19;
int n, rt, t, h[MxN], l[MxN], r[MxN], tin[MxN], tout[MxN], dep[MxN], dp[K][MxN];
pii dp2[K][MxN];

void dfs (int cur, int par, int parl, int parr) {
  tin[cur] = ++t; dep[cur] = dep[par] + 1; dp[0][cur] = (dep[parl] < dep[parr] ? parl : parr);
  if (l[cur]) dfs(l[cur], cur, parl, cur);
  if (r[cur]) dfs(r[cur], cur, cur, parr);
  tout[cur] = t;
}

pii get (int l, int r) {
  int lg = 31 - __builtin_clz(r - l + 1);
  return max(dp2[lg][l], dp2[lg][r - (1 << lg) + 1]);
}

void init(int N, std::vector<int> H) {
  n = N;
  for (int i = 1; i <= n; i++) h[i] = H[i - 1];
  stack<int> st;
  for (int i = 1; i <= n; i++) {
    while (!st.empty() && h[i] > h[st.top()]) l[i] = st.top(), st.pop();
    if (!st.empty()) r[st.top()] = i;
    else rt = i;
    st.emplace(i);
  }
  dfs(rt, 0, 0, 0);
  for (int i = 1; i <= n; i++) dp2[0][i] = {h[i], i};
  for (int i = 1; i < K; i++) {
    for (int j = 1; j <= n; j++) {
      dp[i][j] = dp[i - 1][dp[i - 1][j]];
      dp2[i][j] = max(dp2[i - 1][j], dp2[i - 1][j + (1 << (i - 1))]);
    }
  }
}

int minimum_jumps(int A, int B, int C, int D) {
  int ans = 0;
  int st = get(A + 1, B + 1).second, ed = C + 1;
  if (tin[ed] > tin[st] || tout[st] > tout[ed]) return -1;
  for (int i = K - 1; i >= 0; i--) {
    if (dep[dp[i][st]] >= dep[ed]) st = dp[i][st], ans += (1 << i);
  }
  ans += dep[st] - dep[ed];
  return ans;
}

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