Submission #1101855

#	Time	Username	Problem	Language	Result	Execution time	Memory
1101855		blackslex	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	213 ms	25424 KiB

jumps

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

using namespace std;

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];

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

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 = 0; i < n; i++) l[i] = r[i] = -1;
  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);
  for (int i = 1; i < K; i++) {
    for (int j = 1; j <= n; j++) dp[i][j] = dp[i - 1][dp[i - 1][j]];
  }
}

int minimum_jumps(int A, int B, int C, int D) {
  int ans = 0;
  int st = A + 1, 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++;
  }
  ans += dep[st] - dep[ed];
  return ans;
}

• 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