Given an array nums containing n + 1 integers where each integer is between 1 and n (inclusive), prove that at least one duplicate number must exist. Assume that there is only one duplicate number, find the duplicate one. Example 1: Input:Continue reading “[Leetcode]287. Find the Duplicate Number”
[1,3,4,2,2]Output: 2 Note: 1. You must not modify the array (assume the array is read only). 2. You must use only constant, O(1) extra space. 3. Your runtime complexity should be less than O(n2). 4. There is only one duplicate number in the array, but it could be repeated more than once.
The cycle detection problem is to find the cycle in a sequence, and Floyd’s cycle detection algorithm, aka Tortoise and Hare algorithm, is a two pointers algorithm to detect the cycle and the start of the cycle as well.Continue reading “Floyd’s Cycle Detection Algorithm – [Leetcode]142. Linked List Cycle II”