One Pager Cheat Sheet

• The Two Pointer Technique is an essential tool for software developers to use, especially when faced with technical interviews.
• Pointers are references to objects, and the two pointers technique is used to track and compare array or string indices to save time and space.
• The two-pointer technique is an efficient approach to processing two elements of a data structure, such as an array or list, per loop in order to solve problems involving collections.
• The two-pointer technique is a search algorithm used to solve problems involving collections such as arrays and lists by comparing elements pointed by two pointers and updating them accordingly.
• By initializing two variables pointer_one and pointer_two and evaluating their values with respect to the given target, we can find pairs in an array that sum up to a certain number with a O(n) time complexity.
• Two pointers are used in different programming languages to start from the ends of an array and iteratively narrow in to find thetarget` more efficiently than other techniques.
• We can use two pointers starting from the beginning and end of an already sorted array to check if they 'sum up' to the target, which is done by a simple comparison statement if sum == target.
• The logic applied is to increment the left pointer if the sum of values is less than the target value and decrement the right pointer if it is higher than the target value.
• Understand that if arr[pointer_one] < target-arr[pointer_two], pointer_one should be moved forward to get closer to the desired magnitude.
• The process of using a fast pointer and a slow pointer is another way to apply the two pointer technique, which can have O(n) time complexity and O(1) space complexity.
• Using Slow and Fast Pointers can detect cycles in a linked list, such as when a node points back to a previous node.
• By setting fast to traverse twice as quickly as slow, the distance between them increases at each step.
• If both pointers reach the same node, then there is a cycle present in the linked list.
• The code attached provides an O(n) or linear time complexity.
• Yes, the two pointer technique can reduce both time and space complexity down to O(n), thus improving overall performance.
• Two-pointers are useful for iterating over and combining two sorted arrays.
• The two-pointer technique involves placing two pointers at opposite ends of an array and comparing their values to reverse its order by swapping or shifting items.