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binarySearch.js
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binarySearch.js
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// Given an array and a target integer, return the target's index using binary search
// ITERATIVE APPROACH
const binarySearchIterative = (arr, target) => {
let left = 0;
let right = arr.length - 1;
while (left <= right) {
let mid = left + Math.floor((right-left) / 2);
if (arr[mid] === target) return mid;
if (arr[mid] < target) {
left = mid + 1;
} else {
right = mid - 1;
}
}
return -1;
}
console.log(binarySearchIterative([1,3,5,8,10], 1));
console.log(binarySearchIterative([1,3,5,8,10], 5));
console.log(binarySearchIterative([1,3,5,8,10], 10));
console.log(binarySearchIterative([1,3,5,8,10], 0));
// RECURSIVE APPROACH
const binarySearchRecursive = (arr, target, left = 0, right = arr.length-1) => {
let mid = left + Math.floor((right-left) / 2);
if (arr[mid] === target) return mid;
if (arr[mid] < target) {
left = mid + 1;
} else if (arr[mid] > target) {
right = mid - 1;
} else {
return -1;
}
return binarySearchRecursive(arr, target, left, right);
}
console.log(binarySearchRecursive([1,3,5,8,10], 1));
console.log(binarySearchRecursive([1,3,5,8,10], 5));
console.log(binarySearchRecursive([1,3,5,8,10], 10));
console.log(binarySearchRecursive([1,3,5,8,10], 0));