【LeetCode】在有序数组中找到给定元素或给定元素的插入位置：Search Insert Position

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

代码如下：

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        return distance(nums.begin(), lower_bound(nums.begin(), nums.end(), target));
    }
    
    template<typename ForwardIterator, typename T>
    ForwardIterator lower_bound(ForwardIterator start, ForwardIterator end, T target) {
        while(start != end) {
            auto mid = next(start, distance(start, end)/2);
            if(*mid < target) start = mid + 1;
            else end = mid;
        }
        
        return start;
    }
};