LeetCode35 Search Insert Position

问题描述：
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.

Example 1:

Input: [1,3,5,6], 5
Output: 2
Example 2:

Input: [1,3,5,6], 2
Output: 1
Example 3:

Input: [1,3,5,6], 7
Output: 4
Example 4:

Input: [1,3,5,6], 0
Output: 0
题源：here；完整实现：here
思路：
我们用二分法查找目标值，如果没有目标值就定位到目标值的左边，代码如下：

    int searchInsert(vector<int>& nums, int target) {
        if (target < nums[0]) return 0;
        int left = 0, right = nums.size() - 1;
        while (left <= right){
            int mid = (left + right+1) / 2;
            if (nums[mid] == target) return mid;
            if (left == right) return mid + 1;
            if (nums[mid] > target) right = mid - 1;
            else left = mid;
        }
    }