Bernard Wong
  • Software Engineer
  • Problems
    • Lowest Common Ancestor of a Binary Tree
    • Longest Substring Without Repeating Characters
    • Longest Palindromic Substring
    • Longest Common Prefix
    • Isomorphic Strings
    • Integer to Roman
    • Frog Jump
    • Find the Difference
    • Find k closest elements to a given value
    • Longest Common Subsequence
    • Binary Search Tree from Sorted Array
    • Balanced Binary Tree
    • Sort Using Two Stacks
    • O(1) Stack
    • k-th element to last of a LinkedList
    • Dedup LinkedList
    • Check Rotated String
    • Compress String by Character Count
    • Escape HTML whitespace
    • Check String Permutation
    • Unique String
    • Container With Most Water
    • 4 Sum
    • 3 Sum Closest
    • 3 Sum
    • 2 Sum
    • Maximum Subarray
    • Nested List Weight Sum
    • Palindrome Number
    • Pow(x, n)
    • Regular Expression Matching
    • Remove Nth Node From End of List
    • Reverse Integer
    • Roman to Integer
    • Rotate Array
    • Search a 2D Matrix
    • Shortest Word Distance
    • Two Sum III - Data structure design
    • Valid Parentheses
    • ZigZag Conversion
    • Quicksort
    • Add Two Numbers
    • Best Time to Buy and Sell Stock
    • Letter Combinations of a Phone Number
  • Data Structures
    • Heap
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  1. Problems

Quicksort

PreviousZigZag ConversionNextAdd Two Numbers

Last updated 6 years ago

Extract from

def sort(xs: Array[Int]) {
  def swap(i: Int, j: Int) {
    val t = xs(i); xs(i) = xs(j); xs(j) = t
  }
  def sort1(l: Int, r: Int) {
    val pivot = xs((l + r) / 2)
    var i = l; var j = r
    while (i <= j) {
      while (xs(i) < pivot) i += 1
      while (xs(j) > pivot) j -= 1
      if (i <= j) {
        swap(i, j)
        i += 1
        j -= 1
      }
    }
    if (l < j) sort1(l, j)
    if (j < r) sort1(i, r)
  }
  sort1(0, xs.length - 1)
}

val arr = Array(3,5,7,3,2,6,8,3,5,1,5,2)
sort(arr)
arr mkString ","

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