Problem StatementGiven the head of a singly linked list, determine whether the sequence of values reads identically forward and backward.Example 1:Input: 1 -> 2 Output: falseExample 2:Input: 1 -> 2 -> 2 -> 1 Output: trueApproach 1: Fast and Slow Pointers with In-Place ReversalThis method achieves O(...
Problem Statement Given a sorted integer array nums, remove duplicates in-place sothat each unique element appears no more than twice. Return the new length of the array. Key constraints: Must modify the input array in-place Space complexity must be O(1) The function receives the array by reference...
This review focuses on core techniques for arrays and linked lists, including practical C++ implementations. Arrays The most important concept for array problems is the two-pointer technique. Fast and Slow Pointers When removing or manipulating elements, nested loops lead to O(n²) time complexity. U...
Problem Description Given a sorted array, remove the duplicates in-place such that each element appears only once and return the new length. Do not allocate extra space for another array; you must modify the input array in-place with O(1) extra memory. Example 1: Given numbers = [1, 1, 2], The funct...
D. On AtCoder Conference Problem Statement There is a circular pond with circumference (M). A hut and (N) people are located around the pond. For a real number (x) ((0\leq x < M)), the point (x) is defined as the position clockwise at distance (x) from the hut. The (i)-th person is at point (A_i)...
