博客

 class Solution {
        public int search(int[] nums, int target) {

            if(nums.length==0 ||target<nums[0] || target > nums[nums.length-1]){
                return -1;
            }
            int begin=0;
            int end=nums.length-1;
            int mid = 0;

            while (begin <= end){
                mid = (begin + end)/2;

                if(nums[mid]==target){
                    break;
                }else if( nums[mid] < target){
                    begin=mid+1;
                }else{
                    end = mid-1;
                }

            }
            if(nums[mid]== target){
                return mid;
            }else{
                return -1;
            }

        }
    }