Can min/max of moving window achieve in O(N)?

by

O(N) is possible using Deque data structure. It holds pairs (Value; Index). 

at every step:

  if (!Deque.Empty) and (Deque.Head.Index <= CurrentIndex - T) then 
     Deque.ExtractHead;
  //Head is too old, it is leaving the window

  while (!Deque.Empty) and (Deque.Tail.Value > CurrentValue) do
     Deque.ExtractTail;
  //remove elements that have no chance to become minimum in the window

  Deque.AddTail(CurrentValue, CurrentIndex); 
  CurrentMin = Deque.Head.Value
  //Head value is minimum in the current window

More Related Contents:

  1. maximize the top element of the stack after performing exactly K operations
  2. Algorithm for all subsets of Array
  3. How to sort in-place using the merge sort algorithm?
  4. Easy interview question got harder: given numbers 1..100, find the missing number(s) given exactly k are missing
  5. Finding three elements in an array whose sum is closest to a given number
  6. Given an array of numbers, return array of products of all other numbers (no division)
  7. How to find the kth smallest element in the union of two sorted arrays?
  8. Algorithm to find k smallest numbers in array of n items
  9. Weighted random selection from array
  10. Find the Smallest Integer Not in a List
  11. How to find a duplicate element in an array of shuffled consecutive integers?
  12. How to divide a set into two subsets such that difference between the sum of numbers in two sets is minimal?
  13. Given an array, find out the next smaller element for each element
  14. Binary Search algorithm implementations
  15. Find the 2nd largest element in an array with minimum number of comparisons
  16. Algorithm to rotate an array in linear time
  17. Find all subsets of length k in an array
  18. Maximum single-sell profit
  19. In-place array reordering?
  20. How to find max. and min. in array using minimum comparisons?
  21. Median of 5 sorted arrays
  22. find pair of numbers in array that add to given sum
  23. Regarding in-place merge in an array
  24. Find min/max in a two dimensional array
  25. Interview question: three arrays and O(N*N)
  26. How to find repeating sequence of characters in a given array?
  27. Maximum sum of non consecutive elements
  28. Finding kth smallest number from n sorted arrays
  29. calculating the number of “inversions” in a permutation
  30. Find the first element in a sorted array that is greater than the target

Leave a Comment