Two Pointers: A Top-Rated DSA Pattern Every Coding Interviewee Should Master

The Two Pointers technique is one of the highest-frequency patterns in coding interviews, using two indices instead of one to traverse arrays or strings efficiently. Pointers can move toward each other, in the same direction, or at different speeds depending on the problem type. The approach is especially useful for sorted arrays, palindrome checks, removing duplicates, and pair-sum problems, reducing time complexity from O(n²) to O(n). Common pitfalls include applying two pointers on unsorted arrays where original indices matter, or moving the wrong pointer when adjusting a sum. The next related concept, Sliding Window, builds on pointer logic and tackles a distinct class of problems such as longest substrings and minimum window substrings.