Search Insert Position

Problem

Given a sorted array of distinct integers 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 must write an algorithm with O(log n) runtime complexity.

Constraints

• 1 <= nums.length <= 104
• -104 <= nums[i] <= 104
• nums contains distinct values sorted in ascending order.
• -104 <= target <= 104

Solution

The problem Search Insert Position can be solved by implementing a simple binary search algorithm.

Implementation

/**
 * Definition for singly-linked list.
 * struct ListNode {
 *     int val;
 *     ListNode *next;
 *     ListNode() : val(0), next(nullptr) {}
 *     ListNode(int x) : val(x), next(nullptr) {}
 *     ListNode(int x, ListNode *next) : val(x), next(next) {}
 * };
 */
class Solution
{
  public:
    ListNode *mergeTwoLists(ListNode *list1, ListNode *list2)
    {
        ListNode *head = new ListNode();
        ListNode *cur = head;

        while (list1 && list2)
        {
            if (list1->val < list2->val)
            {
                cur = cur->next = list1;
                list1 = list1->next;
            }
            else
            {
                cur = cur->next = list2;
                list2 = list2->next;
            }
        }
        cur->next = list1 ? list1 : list2;

        return head->next;
    }
};