Find Element in Sorted Array with Duplicates
Prereq: Vanilla Binary Search and Finding the Boundary with Binary Search
Given a sorted array of integers and a target integer, find the first occurrence of the target and return its index. Return -1 if the target is not in the array.
Input:
arr = [1, 3, 3, 3, 3, 6, 10, 10, 10, 100]target = 3
Output: 1
Explanation: The first occurrence of 3 is at index 1.
Input:
arr = [2, 3, 5, 7, 11, 13, 17, 19]target = 6
Output: -1
Explanation:
6 does not exist in the array.