Submission #561337

#	Time	Username	Problem	Language	Result	Execution time	Memory
561337		ian2024	Rainforest Jumps (APIO21_jumps)	C++14	0 / 100	20 ms	28444 KiB

jumps

#include <bits/stdc++.h>

using namespace std;

struct C_HASH {
  static uint64_t splitmix64(uint64_t x) {
    // http://xorshift.di.unimi.it/splitmix64.c
    x += 0x9e3779b97f4a7c15;
    x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
    x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
    return x ^ (x >> 31);
  }

  size_t operator()(uint64_t x) const {
    static const uint64_t FIXED_RANDOM =
        chrono::steady_clock::now().time_since_epoch().count();
    return splitmix64(x + FIXED_RANDOM);
  }
};

mt19937 rng(chrono::system_clock::now().time_since_epoch().count());

typedef pair<int, int> ii;
typedef tuple<int, int, int> iii;
typedef long long ll;

const int INF = 1e9;
const ll INFL = 1e18;
const int MOD = 1000000007;

#define SIZE(a) (int)(a).size()
#define endl '\n'
#define all(x) x.begin(), x.end()
#define ALL(x) begin(x), end(x)

int pos[200005];
int lo[200005][18];
int hi[200005][18];
void init(int N, std::vector<int> H) {
  for (int i = 0; i < 200005; ++i) {
    for (int j = 0; j < 18; ++j) {
      lo[i][j] = INF;
      hi[i][j] = INF;
    }
  }

  for (int i = 0; i < N; ++i) {
    pos[H[i]] = i;
  }

  set<int> s;
  for (int i = N; i >= 1; --i) {
    s.insert(pos[i]);
    auto l = s.lower_bound(pos[i]);
    if (l != s.begin()) {
    	l--;
    	lo[i][0] = H[*l];
    }
    auto r = s.upper_bound(pos[i]);
    if (r != s.end()) hi[i][0] = H[*r];
    if (hi[i][0] < lo[i][0]) {
      swap(hi[i][0], lo[i][0]);
    }
  }

  for (int j = 1; j < 18; ++j) {
    for (int i = 1; i <= N; ++i) {
      if (lo[i][j - 1] != INF) lo[i][j] = lo[lo[i][j - 1]][j - 1];
      if (hi[i][j - 1] != INF) hi[i][j] = hi[hi[i][j - 1]][j - 1];
    }
  }
}

int minimum_jumps(int A, int B, int C, int D) {
  int jumps = 0;
  int curr = A;
  for (int i = 17; i >= 0; --i) {
    if (hi[curr][i] <= C) {
      curr = hi[curr][i];
      jumps += (1 << i);
    }
  }

  for (int i = 17; i >= 0; --i) {
    if (lo[curr][i] <= C) {
      curr = lo[curr][i];
      jumps += (1 << i);
    }
  }

  if (curr != C) return -1;
  return jumps;
}

#ifdef LOCAL_PROJECT
int main() {
  int N, Q;
  assert(2 == scanf("%d %d", &N, &Q));
  std::vector<int> H(N);
  for (int i = 0; i < N; ++i) {
    assert(1 == scanf("%d", &H[i]));
  }
  init(N, H);

  for (int i = 0; i < Q; ++i) {
    int A, B, C, D;
    assert(4 == scanf("%d %d %d %d", &A, &B, &C, &D));
    printf("%d\n", minimum_jumps(A, B, C, D));
  }
  return 0;
}
#else
#include "jumps.h"
#define cerr \
  if (false) cerr
#endif

• 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