AI solution for JavaScript Coding Question on BFE.dev
49. search last index with Binary Search(possible duplicate array)

/**
 * @param {number[]} arr - ascending order array with possible duplicates
 * @param {number} target
 * @returns {number} - last index of target number in arr, -1 if not found
 */
function binarySearchLast(arr, target) {
  // your code here
}

Example:

const arr = [1,2,2,2,3,3,4,5,6];
console.log(binarySearchLast(arr, 2)); // 3
console.log(binarySearchLast(arr, 3)); // 5
console.log(binarySearchLast(arr, 6)); // 8
console.log(binarySearchLast(arr, 0)); // -1