KnightCodes Day 6 JAVA Arrays Method and there use in problem solving.

Описание: ✅ Java Arrays – Built-in Methods & Their Uses (Description)

In this lesson, we explore the most powerful and commonly used built-in methods provided by Java’s Arrays class. These methods make working with arrays easier, faster, and more efficient — especially when solving coding problems and interview questions.

We will understand what each method does, when to use it, how to use it, and how it simplifies our code.

⭐ 1️⃣ Arrays.sort

✔ What it does
Sorts the entire array in ascending order.

✔ When to use
• Before applying binary search
• When you need smallest or largest elements quickly
• When preparing data for comparison
• Competitive programming and LeetCode problems

✔ How it simplifies work
Instead of writing your own sorting algorithm, Java gives you a fast and optimized sort.

⭐ 2️⃣ Arrays.sort(startIndex, endIndex)

✔ What it does
Sorts only a specific portion of the array.
• startIndex is included
• endIndex is excluded

✔ When to use
• When you only want to sort a small part of the array
• When solving problems where only a segment must be arranged
• When optimizing performance for large arrays

✔ Example use cases
• Sorting marks from index 2 to 5
• Sorting just the last half of an array
• Sorting custom ranges in competitive problems

⭐ 3️⃣ Arrays.toString

✔ What it does
Converts the entire array into a readable string format like:
[10, 20, 30, 40]

✔ When to use
• To print arrays without loops
• While debugging code
• Showing output neatly in projects and assignments

✔ Why it’s useful
Java cannot print arrays directly; toString helps display them clearly.

⭐ 4️⃣ Arrays.fill

✔ What it does
Fills the entire array (or part of it) with a single value.

✔ When to use
• Initialize arrays faster
• Reset all values
• Create test data
• Set default values

✔ Example use cases
• Filling marks with zero
• Initializing a boolean array
• Creating a dummy dataset

⭐ 5️⃣ Arrays.compare

✔ What it does
Compares two arrays element by element.

✔ What it returns
• 0 → arrays are equal
• Negative value → array1 is smaller
• Positive value → array1 is greater

✔ When to use
• Sorting-based problems
• Checking dictionary or alphabetical order (lexicographical comparison)
• Validating test cases
• Competitive programming and comparing results

✔ Why it’s powerful
Instead of writing loops for comparison, Java gives us a single method.