Binary Search

class Solution {
    public int search(int[] nums, int target) {
        int start =0;
        int end = nums.length-1;

        int mid = start + (end - start)/2;

        while(start <= end){

            if(nums[mid] == target){
                return mid;
            }

            //right part
            if(target > nums[mid]){
                start = mid +1;
            }

            //left part
            else{  // target < nums[mid]
                end = mid -1;
            }

            mid = start + (end - start)/2;
        }
        return -1;
    }
}