Problem: Find First and Last Position of Element in Sorted Array

med

30 min

Understand how to apply a modified binary search algorithm to identify the first and last positions of a target element in a sorted array. This lesson guides you through implementing an efficient O(log n) solution that handles edge cases and returns [-1, -1] if the element is not found.

Statement

You are given an integer array, nums, that is sorted in non-decreasing order. Your task is to find the first and last indexes of a given value, target, within this array.

If the target does not appear in the array at all, return [-1, -1].

Note: You must write an algorithm with $O(\log n)$ runtime complexity.

Constraints:

$0 \le$ nums.length $\leq 10^5$
$-10^{9} \leq$ nums[i] $\leq 10^{9}$
nums is a non-decreasing array.
$-10^{9} \leq$ target $\leq 10^{9}$

Problem: Find First and Last Position of Element in Sorted Array

med

30 min

Statement

You are given an integer array, nums, that is sorted in non-decreasing order. Your task is to find the first and last indexes of a given value, target, within this array.

If the target does not appear in the array at all, return [-1, -1].

Note: You must write an algorithm with $O(\log n)$ runtime complexity.

Constraints:

$0 \le$ nums.length $\leq 10^5$
$-10^{9} \leq$ nums[i] $\leq 10^{9}$
nums is a non-decreasing array.
$-10^{9} \leq$ target $\leq 10^{9}$

Problem: Find First and Last Position of Element in Sorted Array

Statement

Examples

Understand the problem

Figure it out!

Try it yourself

Problem: Find First and Last Position of Element in Sorted Array

Statement

Examples

Understand the problem

Figure it out!

Try it yourself