Search⌘ K
AI Features
Home
Courses
Grokking the Coding Interview Patterns in Python

Remove Duplicate Letters

Explore how to use stacks to remove duplicate letters from a lowercase string, ensuring each letter appears once and the result is the smallest lexicographical sequence possible. This lesson develops your skills in string manipulation with stacks, emphasizing problem understanding, constraint handling, and optimal ordering.

We'll cover the following...

Statement

You are given a string, s, consisting only of lowercase English letters. Your task is to remove duplicate letters so that:

  1. Each letter appears only once in the resulting string.

  2. The resulting string is the smallest in lexicographical order among all possible results that satisfy the above condition.

Return the final string.

A string, a, is considered lexicographically smaller than string b if:

    ...