Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.

You may assume no duplicates in the array.

Here are few examples.
[1,3,5,6], 5 → 2
[1,3,5,6], 2 → 1
[1,3,5,6], 7 → 4
[1,3,5,6], 0 → 0

思路：二分法，条件怎么写自己给个例子一下子就figure out了。low<=high的原因，如果 1 3 5 6，最后 low=high=0,必须要再过一遍循环把low+1上去，这才是我们想要的位置。

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

35. Search Insert Position