Divide a String Into Groups of Size k — Chunking & Padding Trick Explained | LeetCode #2138

Welcome back! In this video we solve LeetCode Problem #2138 — Divide a String Into Groups of Size k, a clean string simulation problem that teaches one of the most practical and reusable patterns in string processing — fixed-size chunking with padding.

The problem gives us a string s, an integer k, and a fill character. We need to split the string into consecutive groups of exactly k characters. The first group takes characters 0 to k-1, the second takes k to 2k-1, and so on. If the last group has fewer than k characters remaining, we pad it with the fill character until it reaches size k. We return all groups as an array of strings.

We start by tracing through both examples carefully. For s = "abcdefghi" and k = 3, the string divides perfectly into ["abc", "def", "ghi"] with no padding needed. For s = "abcdefghij" and k = 3, the first three groups form perfectly but the last group only has 'j' — so we pad with two 'x' characters to get "jxx", giving us ["abc", "def", "ghi", "jxx"].

The implementation is a clean step-k loop — iterate through the string with a step size of k, slice s[i : i+k] at each step, and append it to the result. After the loop, check if the last chunk is shorter than k and pad it with the fill character repeated the required number of times. The number of fill characters needed is simply k minus the length of the last chunk.#LeetCode #LeetCode2138 #DivideString #StringChunking #PaddingTrick #StringSlicing #FixedSizeGroups #CeilingDivision #DSA #DataStructures #Algorithms #CodingInterview #TechInterviewPrep #FAANGInterview #GoogleInterview #AmazonInterview #LeetCodeEasy #StringSimulation #StepKLoop #OneLinerSolution #CompetitiveProgramming #PatternRecognition #ProblemSolving #CodingChallenge #LearnToCode #BeginnerDSA

Видео Divide a String Into Groups of Size k — Chunking & Padding Trick Explained | LeetCode #2138 канала Krishna