Submission #716166

#	Time	Username	Problem	Language	Result	Execution time	Memory
716166		schiftyfive4	Rainforest Jumps (APIO21_jumps)	C++14	100 / 100	1593 ms	98744 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;

#ifdef LOCAL
#include "debug.hpp"
#else
#define debug(...) "MJ >> LAMELO"
#endif

template <typename T, class F = function<T(const T&, const T&)>>
struct sparse_table {
  int n;
  vector<vector<T>> mat;
  F func;
  sparse_table() {}
  sparse_table(const vector<T>& a, const F& f) : func(f) {
    n = static_cast<int>(a.size());
    int max_log = 32 - __builtin_clz(n);
    mat.resize(max_log);
    mat[0] = a;
    for (int j = 1; j < max_log; j++) {
      mat[j].resize(n - (1 << j) + 1);
      for (int i = 0; i <= n - (1 << j); i++) {
        mat[j][i] = func(mat[j - 1][i], mat[j - 1][i + (1 << (j - 1))]);
      }
    }
  }
  T get(int L, int R) const {
    assert(0 <= L && L <= R && R <= n - 1);
    int lg = 32 - __builtin_clz(R - L + 1) - 1;
    return func(mat[lg][L], mat[lg][R - (1 << lg) + 1]);
  }
};

const int lg = 20;
vector<int> h;
vector<vector<int>> g;
vector<vector<int>> go_low;
vector<vector<int>> go_high;
vector<vector<int>> go_right;
sparse_table<int> st;
int n;

void init(int N, vector<int> H) {
  n = N;
  h = H;
  h.push_back(1e9);
  g.resize(n + 1);
  vector<int> t;
  for (int i = 0; i < n; i++) {
    while (!t.empty() && h[i] > h[t.back()]) {
      t.pop_back();
    }
    if (!t.empty()) {
      g[i].push_back(t.back());
    }
    t.push_back(i);
  }
  go_right = vector<vector<int>>(n + 1, vector<int>(lg));
  t.clear();
  for (int i = n - 1; i >= 0; i--) {
    go_right[i][0] = i;
    while (!t.empty() && h[i] > h[t.back()]) {
      t.pop_back();
    }
    if (!t.empty()) {
      g[i].push_back(t.back());
      go_right[i][0] = t.back();
    }
    t.push_back(i);
  }
  for (int i = 0; i < n; i++) {
    if (g[i].size() == 2 && h[g[i][0]] > h[g[i][1]]) {
      swap(g[i][0], g[i][1]);
    }
  }
  go_low = vector<vector<int>>(n + 1, vector<int>(lg));
  go_high = vector<vector<int>>(n + 1, vector<int>(lg));
  for (int i = 0; i <= n; i++) {
    go_low[i][0] = go_high[i][0] = n;
    if (g[i].size() > 0) {
      go_low[i][0] = g[i][0];
    }
    if (g[i].size() > 1){
      go_high[i][0] = g[i][1];
    }
  }
  for (int b = 1; b < lg; b++) {
    for (int i = 0; i <= n; i++) {
      go_low[i][b] = go_low[go_low[i][b - 1]][b - 1];
      go_high[i][b] = go_high[go_high[i][b - 1]][b - 1];
      go_right[i][b] = go_right[go_right[i][b - 1]][b - 1];
    }
  }
  vector<int> p(n);
  iota(p.begin(), p.end(), 0);
  st = sparse_table<int>(p, [&](int i, int j) { return h[i] > h[j] ? i : j; });
}

int minimum_jumps(int a, int b, int c, int d) {
  int x = st.get(c, d);
  if (h[st.get(b, c - 1)] > h[x]) {
    return -1;
  }
  int l = a;
  int r = b;
  while (l < r) {
    int mid = (l + r) >> 1;
    int pos = st.get(mid, b);
    if (h[pos] > h[x]) {
      l = mid + 1;
    } else {
      r = mid;
    }
  }
  int s = st.get(l, b);
  l = c;
  r = d;
  int val = h[st.get(s, c - 1)];
  while (l < r) {
    int mid = (l + r) >> 1;
    int pos = st.get(c, mid);
    if (h[pos] > val) {
      r = mid;
    } else {
      l = mid + 1;
    }
  }
  int t = l;
  int ans = 0;
  for (int b = lg - 1; b >= 0; b--) {
    int ns = go_high[s][b];
    if (h[ns] < h[t]) {
      s = ns;
      ans += (1 << b);
    }
  }
  if (c <= go_right[s][0] && go_right[s][0] <= d) {
    return ans + 1;
  }
  if (h[go_high[s][0]] < h[x]) {
    assert(go_high[s][0] < s);
    s = go_high[s][0];
    // assert(s < c);
    // s = go_low[s][0];
    // assert(c <= s && s <= d);
    return ans + 2;
  }
  assert(s < c);
  assert(h[s] < h[t]);
  assert(h[go_high[s][0]] > h[x]);
  for (int b = lg - 1; b >= 0; b--) {
    int ns = go_low[s][b];
    if (h[ns] <= h[t]) {
      s = ns;
      ans += (1 << b);
    }
  }
  return ans;
}

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