Submission #979917

#	Time	Username	Problem	Language	Result	Execution time	Memory
979917		Tsagana	Rainforest Jumps (APIO21_jumps)	C++14	48 / 100	783 ms	42756 KiB

jumps

#include "jumps.h"

//OP
#include<bits/stdc++.h>

#define all(x) x.begin(), x.end()
#define pi pair<int, int >
#define pq priority_queue
#define lb lower_bound
#define ub upper_bound
#define pb push_back
#define eb emplace_back
#define mset multiset
#define F first
#define S second
#define meta int M = (L + R) / 2, x = 2 * id + 1, y = x + 1

using namespace std;

bool one;
 
struct tree {
  int n;
  int lj[200005];
  int rj[200005];
  int jump[200005][20];
  int jump2[200005][20];
  vector<int> h;
  pi t[800005];

  void build(int id, int L, int R) {
    if (L == R) {t[id] = {h[L], L}; return ;}
    meta;
    build(x, L, M);
    build(y, M + 1, R);
    t[id] = max(t[x], t[y]);
  } void build() {build(0, 0, n-1); return ;}
 
  pi query(int id, int L, int R, int l, int r) {
    if (R <  l || r <  L) return {-2e9, -1};
    if (l <= L && r >= R) return t[id];
    meta;
    return max(query(x, L, M, l, r), query(y, M + 1, R, l, r));
  } pi query(int L, int R) {return query(0, 0, n-1, L, R);}

  void take_jump(vector<int> H) {
    stack<int> st;
    for (int i = 0; i < n; i++) {
      while (!st.empty() && H[st.top()] < H[i]) st.pop();
      if (st.empty()) lj[i] = -1;
      else lj[i] = st.top();
      st.push(i);
    }

    while (!st.empty()) st.pop();
    for (int i = n-1; i >= 0; i--) {
      while (!st.empty() && H[st.top()] < H[i]) st.pop();
      if (st.empty()) rj[i] = n;
      else rj[i] = st.top();
      st.push(i);
    }
  }

  void set_jump() {
    for (int i = 0; i < n; i++) {
      int mx = lj[i], mx2 = rj[i];

      if (mx == -1) mx = n;
      if (h[mx] < h[mx2]) swap(mx, mx2);

      jump[i][0] = mx;
      jump2[i][0] = mx2;
    }

    jump[n][0] = jump2[n][0] = n;

    for (int j = 1; j < 20; j++)
    for (int i = 0; i <= n; i++)
      jump[i][j] = jump[jump[i][j-1]][j-1];

    for (int j = 1; j < 20; j++)
    for (int i = 0; i <= n; i++)
      jump2[i][j] = jump2[jump2[i][j-1]][j-1];
  }

  int count(int A, int B, int C, int D) {
    vector<int> mindis(n, 2e9);
    pq<pi> q;
    for (int i = A; i <= B; i++) {mindis[i] = 0;q.push({0, i});}
    
    while(!q.empty()) {
      int i = q.top().F, s = q.top().S; q.pop();

      if (mindis[s] != i) continue;
      if (s >= C && s <= D) return i;
      
      if (lj[s] >= 0 && mindis[lj[s]] > i + 1) {
          mindis[lj[s]] = i + 1;
          q.push({i + 1, lj[s]});
      }
      if (rj[s] < n && mindis[rj[s]] > i + 1) {
          mindis[rj[s]] = i + 1;
          q.push({i + 1, rj[s]});
      }
    }
    return -1;
  }

  int count(int A, int B, int C) {
    A = query(max(A, lj[C] + 1), min(B, rj[C] - 1)).S;
    if (A == -1) return -1;
    
    int ans = 0;

    for (int i = 19; i >= 0; i--)
    if (h[jump[A][i]] < h[C]) {A = jump[A][i]; ans += (1 << i);}
    if (jump[A][0] == C) return ans + 1;

    for (int i = 19; i >= 0; i--)
    if (h[jump2[A][i]] < h[C]) {A = jump2[A][i]; ans += (1 << i);}
    if (jump2[A][0] == C) return ans + 1;
    
    return -1;
  }
} T;
 
void init(int N, std::vector<int> H) {
  T.n = N; T.h = H;
  T.take_jump(H);
  T.build();
  T.h.pb(N + 1);
  T.set_jump();

  one = 1;
  for (int i = 0; i < N; i++) if (H[i] != i+1) {one = 0; break;}
}
 
int minimum_jumps(int A, int B, int C, int D) {
  if (C == D) return T.count(A, B, C);
  if (one) return C-B;
  return T.count(A, B, C, D);
}

//ED

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