704. Binary Search

O(log n ) .

문제이름도 이진탐색이다.

const search = function(nums, target) {
    let start = 0,end = nums.length-1
    while(start <= end){
        let mid = Math.floor((start+end)/2)
        if(nums[mid] == target){
            return mid
        }else if(nums[mid] < target){
            start = mid+1
        }else{
            end = mid-1
        }
    }
    return -1
};