binary-search-二分查找

class Solution {
    public int search(int[] nums, int target) {
        int left = 0,right = nums.length - 1;
        while(left <= right ){
            int mid = (right - left) / 2 + left;
            int num = nums[mid];
            if( num == target){
                return mid;
            } else if ( num > target){
                right = mid - 1;
            } else {
                left = mid + 1;
            }
        }
        return -1;
    }
}