LeetCode Search Insert Position

思想：

二分查找， 时间复杂度O(logN)。

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        int i = 0, j = nums.size() - 1;
        while(i <= j) {
            int mid = (i + j) / 2;
            if(nums[mid] == target) {
                return mid;
            }else if(nums[mid] < target) {
                i = mid + 1;
            }else {
                j = mid - 1;
            }
        }
        return j + 1;
    }
};