Submission #922299

#	Time	Username	Problem	Language	Result	Execution time	Memory
922299		Arp	Rainforest Jumps (APIO21_jumps)	C++17	0 / 100	4098 ms	5844 KiB

jumps

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

const int N = 2e5 + 10;
int ml[N],mr[N];
int best[N];
int arr[N];
const int inf = 1e9;
int MAXN;
bool one = true;
void init(int n,vector<int> a){
  for(int i = 1;i<=n;i++){
    ml[i] = 0;
    mr[i] = n + 1;
    arr[i] = a[i - 1];
    one &= (arr[i] == i);
  }  
  MAXN = n;
  arr[0] = arr[n + 1] = inf;
  stack<int> lg;
  for(int i = 1;i<=n;i++){
    while(lg.size() > 0 && arr[lg.top()] < arr[i]) lg.pop();
    if(lg.size() > 0){
      ml[i] = lg.top();
    }
    lg.push(i);
  }
  stack<int> rg;
  for(int i = n;i >= 1;i--){
    while(rg.size() > 0 && arr[rg.top()] < arr[i]) rg.pop();
    if(rg.size() > 0){
      mr[i] = rg.top();
    }
    rg.push(i);
  }
  for(int i = 1;i<=n;i++){
    if(ml[i] > 0 && arr[i] > arr[ml[i]]){
      best[i] = ml[i];
    }else{
      best[i] = mr[i];
    }    
    // cout << best[i] << " ";
  }
  // cout << '\n';
}

int minimum_jumps(int a,int b,int c,int d){
  a ++,b ++;
  c ++,d ++;
  // if(one) return c - b;  
  int m2 = c;
  for(int i = c;i <= d;i ++){
    if(arr[i] > arr[m2]) m2 = i;
  }
  int m1 = a;
  int maxi = -1;
  for(int i = a;i <= b;i++){
    if(arr[i] > maxi && arr[i] < arr[m2]){
      maxi = arr[i];
      m1 = i;
    }
  }
  if(maxi == -1){
    assert(!one);
    return -1;
  }
  int last = m1;
  int ans = 0;
  while(arr[best[last]] < arr[m2]){
    if(last >= c && last <= d) return ans;
    if(mr[last] >= c && mr[last] <= d) return ans + 1;
    last = best[last];
    assert(last < d && last != MAXN);
    ans ++;
  }
  // assert(last >= c && last <= d);
  while(!(last >= c && last <= d)){
    if(arr[last] > arr[m2] || last > d){
      assert(!one);
      return -1;
    }
    last = mr[last];
    ans ++;
  }
  return ans;
}

• 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