leetcode 704题解

class Solution {
    public int search(int[] nums, int target) {
        int left = 0;//左界限
        int right = nums.length-1;//右界限
        while(left <= right){
            int mid = (left + right)/2;//二分取中间
            //如果目标比中间值大，缩短左边界
            if(target > nums[mid])  left = mid + 1;
            //如果目标比中间值小，缩短右边界
            else if(target < nums[mid])  right = mid - 1;
            //找到目标返回
            else if(target == nums[mid]) return mid;
        }
        return -1;
    }
}