Stack Bash - Master data structures and algorithms

Find duplicate number in array

Medium
Given an n size array of integers 1..n with exactly one duplicate number, write a function that returns the duplicate number.
Some examples:
  1. find_duplicate([1, 3, 2, 3]) should return 3
  2. find_duplicate([1, 2, 5, 4, 5, 3]) returns 5
  3. find_duplicate([1, 2, 1, 3]) returns 1

Solution

6 Essential Primitives Coding Interview Problems

Master Primitives by trying the coding challenges below.
  1. 1.Swap bitsEasy
  2. 2.Power of twoEasy
  3. 3.Count bitsMedium
  4. 4.Reverse bitsMedium
  5. 5.Find duplicateMedium
  6. 6.Bitwise additionHard
Previous Lesson
Reverse bits
Next Lesson
Bitwise addition

Want to confidently pass your next coding interview?

Stack Bash helps new and veteran software engineers master data structures and algorithms for technical interviews.