Binary Search

binary_search.php

let arr = [-2, 3, 4, 7, 8, 9, 11, 13];
let arr2 = [13, -2, 3, 4, 7, 8, 9, 11];
let arr3 = [8, 9, 11, 13, -2, 3, 4, 7];


function binarySearch(arr, target){
  left = 0;
  right = arr.length - 1;
  
  while(left <= right){
    mid = Math.floor((left + right)/ 2);
    if(arr[mid] == target){
      return mid;
    }else if(arr[mid] < target){
      left = mid + 1;
    }else if(arr[mid] > target){
      right = mid - 1;
    }
  }
  
  return -1;
}

binarySearch(arr3, 11)