Today I solved Letter Combinations of a Phone Number using JavaScript and a classic Backtracking approach.
The problem is simple to understand but great for practicing recursion. Each digit from 2 to 9 represents a set of letters, similar to the keys on a traditional phone keypad. For example, 2 maps to abc and 3 maps to def. For the input "23", the expected combinations are: ["ad","ae","af","bd","be","bf","cd","ce","cf"] 💡 Approach I first created a phoneMap object to store the letter mapping for eac…