Submission #413805

#	Time	Username	Problem	Language	Result	Execution time	Memory
413805		flashmt	Rainforest Jumps (APIO21_jumps)	C++17	4 / 100	1437 ms	55852 KiB

jumps

#include <bits/stdc++.h>
using namespace std;
const int N = 200200;
const int LG = 18;
#define db(x) cerr << #x << " = " << x << endl

int n, l[N], r[N], toL[N][LG], toR[N][LG], maxH[N][LG];
vector<int> h;

void initEdges()
{
  vector<pair<int, int>> sortedH;
  for (int i = 0; i < n; i++)
    sortedH.push_back({h[i], i});
  sort(sortedH.begin(), sortedH.end(), greater<pair<int, int>>());
  set<int> s;
  s.insert(-1);
  s.insert(n);
  for (auto [_, i] : sortedH)
  {
    auto it = s.lower_bound(i);
    r[i] = *it;
    l[i] = *(--it);
    s.insert(i);
  }
}

void constructTable()
{
  memset(toL, -1, sizeof toL);
  memset(toR, -1, sizeof toR);
  for (int i = 0; i < n; i++)
  {
    toL[i][0] = l[i];
    toR[i][0] = r[i];
    maxH[i][0] = h[i];
  }

  for (int j = 0; j + 1 < LG; j++)
    for (int i = 0; i < n; i++)
    {
      if (toL[i][j] >= 0)
        toL[i][j + 1] = toL[toL[i][j]][j];
      if (toR[i][j] >= 0)
        toR[i][j + 1] = toR[toR[i][j]][j];
      if (i + (1 << j) < n)
        maxH[i][j + 1] = max(maxH[i][j], maxH[i + (1 << j)][j]);
    }
}

void init(int N, vector<int> H) {
  n = N;
  h = H;
  h[n] = 0;
  initEdges();
  constructTable();
}

int getMaxH(int l, int r)
{
  int bit = 31 - __builtin_clz(r - l + 1);
  return max(maxH[l][bit], maxH[r - (1 << bit) + 1][bit]);
}

int between(int x, int y, int z)
{
  return y <= x && x <= z;
}

int calcDist(int s, int from, int maxDestH)
{
  int dist = 0;
  for (int i = LG - 1; i >= 0; i--)
  {
    int x = toR[s][i];
    if (x >= 0 && x < from && h[x] < maxDestH)
    {
      dist |= 1 << i;
      s = x;
    }
  }
  return h[s] <= maxDestH ? dist + 1 : n;
}

int minimum_jumps(int A, int B, int C, int D) {
  int s = B, maxDestH = getMaxH(C, D);
  for (int i = LG - 1; i >= 0; i--)
  {
    int x = toL[s][i];
    if (x >= A && x < n && h[x] < maxDestH)
      s = x;
  }

  if (h[s] > maxDestH)
    return -1;

  if (between(l[s], C, D) || between(r[s], C, D))
    return 1;

  int ans = calcDist(s, C, maxDestH);
  if (l[s] >= 0 && l[s] < n)
    ans = min(ans, calcDist(l[s], C, maxDestH) + 1);

  return ans < n ? ans : -1;
}

• Subtask 1: 4 / 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