C++实现LeetCode(35.搜索插入位置)

[LeetCode] 35. Search Insert Position 搜索插入位置

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

这道题基本没有什么难度，实在不理解为啥还是 Medium 难度的，完完全全的应该是 Easy 啊（貌似现在已经改为 Easy 类了），三行代码搞定的题，只需要遍历一遍原数组，若当前数字大于或等于目标值，则返回当前坐标，如果遍历结束了，说明目标值比数组中任何一个数都要大，则返回数组长度n即可，代码如下：

解法一：

class Solution {
public:
    int searchInsert(vector<int>& nums, int target) {
        for (int i = 0; i < nums.size(); ++i) {
            if (nums[i] >= target) return i;
        }
        return nums.size();
    }
};

解法二：

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