LeetCode 75 C++ | Step-by-Step Solutions (LAN Academy) - LeetCode 62: Unique Paths — 2D DP Explained (O(n) Space)

Solve LeetCode 62 — Unique Paths using 2D Dynamic Programming (grid DP). A robot starts at the top-left of an m×n grid and can only move Right or Down. We compute how many unique paths reach the bottom-right. DP Idea Let dp[j] be the number of ways to reach the current cell in column j (rolling array). Transition: dp[j] = dp[j] + dp[j-1] Where: dp[j] = ways from Up dp[j-1] = ways from Left Complexity Time: O(m·n) Space: O(n) If this helped, subscribe for more clean LeetCode explanations (DP, Greedy, Graphs). Playlist (DP / Patterns): https://www.youtube.com/playlist?list=PLF0G-7pZcOzYreGYMTEJoOPNIE782wS7H LAN Academy: https://www.youtube.com/@lanacademy9521 #LeetCode #DynamicProgramming #CodingInterview #CPlusPlus #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 @reper #foryou #viral #reper #urmaritori #for