Backtracking from yesterday's mistakes...
Backtracking from yesterday's mistakes...
Use two pointers to traverse arrays and linked lists efficiently
Given a sorted array of integers and a target sum, find two numbers that add up to the target.
Given n non-negative integers representing heights at positions 0 to n-1, find two positions that together with the x-axis form a container that holds the most water.
Given a linked list (or any sequence with a "next" function), determine if it contains a cycle.
Given a linked list, find the middle node.
Given a sorted array, remove duplicates in-place such that each element appears only once.
Given an array of integers, move all zeroes to the end while maintaining the relative order of non-zero elements.
Given a string, find the longest substring that reads the same forwards and backwards.
Master the fundamental pattern. Each problem teaches you when and how to apply this technique.