You are given a sorted array of integers and a target value. Your task is to find the index of the target element using an efficient algorithm.

Return the index of the target if it exists in the array. Otherwise, return 

Your solution must have a time complexity of 

Return the index of the target element using 0-based indexing. If the element is not present, return 

You are given a sorted array of integers and a target value. Find the index of the element whose value is closest to the target.

If the target is already present in the array, return its index.

You are given an unsorted array of integers. Sort the array in non-decreasing order using the 

The sorting must be done by modifying the original array.

The smallest element is selected in each iteration and placed in its correct position.

Given an array of integers, find the sum of all elements using recursion.