Two pointers

Introduction

A common interview technique that utilizes two pointers to traverse through an iterable data structure, usually an array

Variations

• Both pointers moving in the same direction
• Pointers moving in opposite directions
  • eg. each end of an array
• Sliding Window
  • A function is performed on values between the pointer
    • eg. isSubstringUnique()

Time Complexity

• If we naively compare values in an array, the time complexity is O(n^2)
• With two pointers the time complexity becomes O(n)