LeetCode 62: Unique Paths — Step-by-Step Visual Trace

📰 Dev.to · tracelit

Learn to solve the Unique Paths problem on LeetCode using dynamic programming and visual tracing to find the number of paths from top-left to bottom-right in an m x n grid

intermediate Published 9 Apr 2026

Action Steps

Define the problem and identify the constraints: you can only move right or down in an m x n grid
Initialize a 2D array to store the number of unique paths to each cell
Fill in the base cases: there is only one way to reach each cell in the first row and column
Use dynamic programming to fill in the rest of the array: the number of unique paths to each cell is the sum of the number of unique paths to the cell above and to the left
Return the number of unique paths to the bottom-right cell

Who Needs to Know This

This problem is relevant to software engineers and developers who want to improve their problem-solving skills and prepare for technical interviews. It can be solved by individuals or teams looking to practice dynamic programming and algorithmic thinking.

Key Insight

💡 The number of unique paths to each cell can be calculated using the formula: dp[i][j] = dp[i-1][j] + dp[i][j-1]