binary-search-iterative.ts

function BinarySearchIterative(array: number[], key: number): number {
    let [startIndex, lastIndex] = [0, array.length];
    let mid = Math.floor((startIndex + lastIndex) / 2);
    while (startIndex <= lastIndex) {
        if (key === array[mid]) {
            return mid;
        } else if (key < array[mid]) {
            lastIndex = mid - 1;
        } else {
            startIndex = mid + 1;
        }
        mid = Math.floor((startIndex + lastIndex) / 2);
    }
    return -1;
}