breaking the Leetcode 316: Remove Duplicate Letters nilesh

Unraveling the Mystery of Leetcode 316

When it comes to coding, we often find ourselves wrestling with complex challenges, and that's where Leetcode comes to the rescue. Leetcode offers a treasure trove of coding problems to sharpen our skills. Today, we're going to delve into one such problem: Leetcode 316 - Remove Duplicate Letters. But don't be intimidated by the name; we're here to break it down and make it as simple as a game of tic-tac-toe!

Understanding Leetcode 316 - Remove Duplicate Letters

So, what's the deal with Leetcode 316 ? Imagine you're given a string. Your task is to remove the duplicate letters to make it the smallest lexicographically sorted result. Still not clear? Let's take an example to make it crystal clear.
Consider the string "bcabc." To solve this problem, we need to find the smallest lexicographically sorted string after removing the duplicate letters. In this case, the answer would be "abc." But how do we achieve this result programmatically?

The Power of Stack

You might have heard that in programming, a stack is your best friend. Well, here's a situation where it truly shines. We can utilize a stack to help us keep track of the characters and their positions. This is crucial because we want to maintain the order of the characters while removing duplicates.
We traverse the given string and push each character onto the stack if it's not already in there. If we encounter a character that's already in the stack and it's smaller than the top character of the stack, we pop the character from the stack and push the new character. This way, we are ensuring the smallest lexicographically sorted result. It's like arranging books on a shelf - always keep the smallest one on the top.

Algorithm in Action

Let's run through an example. Take the string "bcabc" again:

1. We start with an empty stack.
2. We encounter 'b' and push it onto the stack.
3. We encounter 'c' and push it onto the stack.
4. We encounter 'a' - here's where it gets interesting. 'a' is smaller than 'c', so we pop 'c' and push 'a' onto the stack.
5. We encounter 'b' again, but 'b' is also smaller than 'c', so we pop 'c' and push 'b' onto the stack.
6. Finally, the stack contains 'a', 'b', and 'c' in the desired order, and we return this as the smallest lexicographically sorted result.

Coding It Up

Implementing this algorithm in code is a great exercise. You'll be amazed at how efficient and elegant this solution is. Don't worry if you don't get it right on the first try; coding is all about learning from mistakes and improving.
Here's a simple Python function to remove duplicate letters from a string:
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For the code please check our blog - www.nileshblog.tech/leetcode-316 or link attached in content.

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Leet code 316 is a wonderful exercise to enhance your coding skills, and the concept of removing duplicate letters while maintaining the lexicographical order is a valuable one to understand. Using a stack makes this problem surprisingly simple, and you'll find it useful in many real-world situations. So, next time you face a string manipulation problem, remember the power of a stack and how it helped us crack Leetcode 316! Happy coding!