Submission #569387

#	Time	Username	Problem	Language	Result	Execution time	Memory
569387		Turkhuu	Rainforest Jumps (APIO21_jumps)	C++17	60 / 100	4022 ms	64612 KiB

jumps

#include "jumps.h"
#include <bits/stdc++.h>
using namespace std;
const int L = 18;
const int inf = 1000000000;
int n;
vector<int> a;
vector<vector<int>> lo, hi, g;
bool subtask1 = true;
void init(int N, vector<int> H){
  n = N, a = H;
  g.resize(n);
  lo.assign(n, vector(L, -1));
  hi.assign(n, vector(L, -1));
  for(int i = 1; i < n; i++){
    if(a[i - 1] > a[i]){
      subtask1 = false;
    }
  }
  vector<int> idx(n);
  for(int i = 0; i < n; i++){
    idx[--a[i]] = i;
  }
  set<int> s;
  for(int i = n - 1; i >= 0; i--){
    auto j = s.lower_bound(idx[i]);
    int l = -1, r = -1;
    if(j != s.end()){
      r = a[*j];
      g[idx[i]].push_back(*j);
    }
    if(j != s.begin()){
      l = a[*prev(j)];
      g[idx[i]].push_back(*prev(j));
    }
    if(l != -1 && (r == -1 || l >= r)){
      lo[i][0] = r;
      hi[i][0] = l;
    } else{
      lo[i][0] = l;
      hi[i][0] = r;
    }
    s.insert(idx[i]);
  }
  for(int j = 1; j < L; j++){
    for(int i = 0; i < n; i++){
      if(lo[i][j - 1] != -1){
        lo[i][j] = lo[lo[i][j - 1]][j - 1];
      }
      if(hi[i][j - 1] != -1){
        hi[i][j] = hi[hi[i][j - 1]][j - 1];
      }
    }
  }
}
int minimum_jumps(int A, int B, int C, int D){
  if(subtask1){
    return C - B;
  }
  if(A == B && C == D){
    int H = a[A], G = a[C], c = 0;
    for(int i = L - 1; i >= 0; i--){
      if(hi[H][i] != -1 && hi[H][i] <= G){
        H = hi[H][i];
        c += 1 << i;
      }
    }
    for(int i = L - 1; i >= 0; i--){
      if(lo[H][i] != -1 && lo[H][i] <= G){
        H = lo[H][i];
        c += 1 << i;
      }
    }
    if(H != G){
      c = -1;
    }
    return c;
  }
  queue<int> q;
  vector<int> d(n, inf);
  for(int i = A; i <= B; i++){
    d[i] = 0;
    q.push(i);
  }
  while(!q.empty()){
    int i = q.front();
    q.pop();
    if(C <= i && i <= D){
      return d[i];
    }
    for(int j : g[i]){
      if(d[i] + 1 < d[j]){
        d[j] = d[i] + 1;
        q.push(j);
      }
    }
  }
  return -1;
}

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