DSA Problem Solving — Day 5 and 6

Welcome to Day 5 & 6 of my #DSAinJavaScript journey!
This week, I tackled a mix of string and array problems — each one sharpening core logic and edge case handling.

Here’s a quick breakdown with examples, approach, and code 🧠💻👇

✅ Problem 1: Count Negative Numbers in an Array

🔍 Problem:

Given an array, count how many numbers are negative.

📦 Example:

 Input: [2, -9, 17, 0, 1, -10, -4, 8] Output: 3 

🧠 Approach:

• Loop through each element.
• If it's less than 0, increase the counter.
• Return the counter.

✅ Solution:

function countNegative(arr) { let counter = 0; for (let i = 0; i < arr.length; i++) { if (arr[i] < 0) counter++; } return counter; } 

✅ Problem 2: Find the Largest Number in an Array

🔍 Problem:

Find the maximum value in a given array.

📦 Example:

 Input: [4, 8, 7, 2, 17, 7, 3, 25, 8] Output: 25 

🧠 Approach:

• Start with -Infinity so even negative values are handled.
• Loop through array, update if you find a larger number.

✅ Solution:

function findLargestNumber(arr) { let largest = -Infinity; for (let i = 0; i < arr.length; i++) { if (arr[i] > largest) { largest = arr[i]; } } return largest; } 

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✅ Problem 3: Capitalize the Title

🔍 Problem:

Capitalize each word in a title based on length:

• If word length ≤ 2 → lowercase.
• Else → capitalize first letter, lowercase rest.

📦 Example:

 Input: "First leTTeR of EACH Word" Output: "First Letter of Each Word" 

🧠 Approach:

• Use split(' ') to break the string.
• Use map() to apply formatting based on length.

✅ Solution:

function capitalizeTitle(title) { return title .split(' ') .map(word => word.length <= 2 ? word.toLowerCase() : word[0].toUpperCase() + word.slice(1).toLowerCase() ) .join(' '); } 

✅ Problem 4: Reverse Words in a String III

🔍 Problem:

Reverse every word in a string without changing the word order.

📦 Example:

Input: "Let's take LeetCode contest" Output: "s'teL ekat edoCteeL tsetnoc" 

🧠 Approach:

• Split the string into words.
• Reverse each word using split(''), reverse(), and join('').
• Rejoin with ' '.

✅ Solution:

function reverseWords(s) { return s .split(' ') .map(word => word.split('').reverse().join('')) .join(' '); }