LeetCode 75 C++ | Step-by-Step Solutions (LAN Academy) - 1071 Greatest Common Divisor of Strings (C++) | String GCD Trick | LeetCode 75 #02

LeetCode 75 C++ playlist: https://www.youtube.com/playlist?list=PLF0G-7pZcOza_jyAxwMpa5KnK3vST5smK Comment “NEXT” for the next problem link. Most people overthink this problem. The fastest way to solve it is a simple “string GCD” test that instantly tells you whether a common base pattern exists — then one gcd on lengths gives the answer. In this video, I solve **LeetCode 1071: Greatest Common Divisor of Strings** in **C++** with a clean, interview-ready approach: - First, we verify both strings are built from the same repeating pattern using one powerful check: (str1 + str2) == (str2 + str1) - If true, the length of the greatest divisor string is: gcd(str1.length(), str2.length()) - The answer is the prefix: str1.substr(0, gcdLen) Why this works (quick intuition): If two strings come from the same repeating base, swapping their concatenation order doesn’t change the result. If the concatenations differ, there is no string that can divide both — return "". What you’ll learn (and what interviewers want to see): - How to detect a shared repeating pattern in O(n) - How numeric gcd translates directly to strings - A minimal, robust C++ solution (no brute force, no extra loops) - Edge cases that break naive solutions (e.g., "LEET" vs "CODE", "AAAAAB" vs "AAA") Examples: "ABCABC" + "ABC" → "ABC" "ABABAB" + "ABAB" → "AB" "LEET" + "CODE" → "" "AAAAAB" + "AAA" → "" Problem link: https://leetcode.com/problems/greatest-common-divisor-of-strings/ More clear C++ LeetCode explanations (LeetCode 75): https://lanacademy-school.thinkific.com/courses/leetcode75 Did you first think “brute force all divisors” or did you see the gcd pattern immediately? Comment your first instinct. Follow LAN Academy: Website: https://lanacademy-school.thinkific.com YouTube: @lanacademy9521 X (Twitter): https://x.com/SolutionsLan #LeetCode #cpp #BitManipulation#leetcode #leetcodecoding #leetcodesolution #leetcodechallenge #faang #fang #computerscience #cs #codingtiktok #coding #codinglife #boostofhope #fyp #codinginterview #softwareengineer #swe #tech #foryou #python #learntocode #google #techtok #programming #algorithms #learntocode #1071 #bac #blink #blind @reper #foryou #viral #reper #urmaritori #for