Challenge 1: Single Number
Explore how to find the single non-repeated element in an array where every other element appears twice. Learn to apply the bitwise XOR operator for an optimal O(n) time solution, surpassing naive and hashtable approaches. This lesson strengthens your problem-solving with bit manipulation focusing on XOR's practical use.
Introduction
In this question, every element appears twice except one element, which is our answer.
Let’s see how to achieve this using the XOR operator.
Problem statement
We need to write a program that finds the element that is not repeated.
Input: nums = { 4, 1, 2, 9, 1, 4, 2 }
Output: 9
Explanation: Except for 9, all elements are repeated.
Assume n is non-negative.
Hint: Use the ^ operator to achieve this.
Solution
We solve this using naive, and then we move to solve it in a more optimal way.
Brute force
This is a naive approach. We traverse the entire array twice to achieve this, which is not optimal.
Algorithm
Iterate the elements using two for loops and find the one that is not repeating.
Complexity analysis
Time Complexity: O()
Space Complexity: ...