Day 6 – 100 days of DSA challenge

Challenge: Valid Parentheses

Welcome to Day 6 of our 100 Days DSA Challenge! 🚀 Today’s challenge takes us into the realm of valid parentheses – a classic problem that tests our understanding of balancing and sequencing brackets.

The Challenge:

Given a string containing the characters ‘(‘, ‘)’, ‘{‘, ‘}’, ‘[‘, and ‘]’, our task is to determine if the input string is valid according to the following rules:

1. Open brackets must be closed by the same type of brackets.
2. Open brackets must be closed in the correct order.

Example:

const s = "()[]{}";
// Output: true

Challenge Yourself:

Before exploring the solution, challenge yourself to think about how you would approach this problem. Can you optimize the code further?

The Solution:

const validParentheses = (str) => {
    const openParentheses = [];
    const openClose = {
        ")": "(",
        "]": "[",
        "}": "{"
    };

    for (let i = 0; i < str.length; i++) {
        if (str[i] == "(" || str[i] == "[" || str[i] == "{") {
            openParentheses.push(str[i]);
        } else {
            const openBracket = openParentheses.pop();
            if (openBracket != openClose[str[i]]) {
                return false;
            }
        }
    }

    return true;
}

Solution Logic:

Initialize Stacks and Mapping:

• We use an array (openParentheses) as a stack to keep track of open brackets.
• We create a mapping (openClose) that associates closing brackets with their corresponding opening brackets.

Iterate Through the String:

• We iterate through the input string and process each character.

Handle Opening Brackets:

• If the character is an opening bracket, we push it onto the stack.

Handle Closing Brackets:

• If the character is a closing bracket, we pop the last item from the stack and check if it matches the expected opening bracket.

Check for Validity:

• If the brackets are valid, the stack will be empty at the end of the iteration.

Return the Result:

• We return true if the brackets are valid and false otherwise.

Conclusion:

Congratulations on completing Day 6 of our DSA Challenge! Validating parentheses is a crucial skill in coding, and mastering it enhances your algorithmic abilities. Stay tuned for tomorrow’s challenge, and keep the coding spirit alive!

Happy coding! 🌟💻

#100DaysDSAChallenge #DataStructures #Algorithms #ProgrammingCommunity #CodeNewbie