Array Basics 10 XP Easy

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Welcome to Arrays — the most fundamental data structure in all of programming! 📚

💡 Think of it like this: An array is like a row of lockers in a school hallway. Each locker has a number (index), and each locker holds one item. You can quickly open any locker if you know its number!

# Creating arrays (Python uses lists)
nums = [10, 20, 30, 40, 50]

# Accessing by index (starts at 0!)
print(nums[0])    # 10 (first element)
print(nums[2])    # 30 (third element)
print(nums[-1])   # 50 (last element)

# Length
print(len(nums))  # 5

Key array operations and their Big O:

✅ Access by index → O(1) — instant! Just go to that locker
✅ Append to end → O(1) — add at the end
⚠️ Insert at beginning/middle → O(n) — everyone has to shift over!
⚠️ Search for a value → O(n) — check every locker one by one
✅ Update by index → O(1) — change what's in a specific locker

Arrays are used in almost EVERY coding interview question. Master arrays and you master half of DSA! 💪

📋 Instructions

Write a function `array_operations(arr)` that takes a list of integers and returns a dictionary with: - `'sum'` — sum of all elements - `'min'` — minimum element - `'max'` — maximum element - `'length'` — number of elements - `'reversed'` — the list reversed Print the result for the test case.

Use Python built-ins: sum(arr), min(arr), max(arr), len(arr). For reversed, use arr[::-1] which creates a reversed copy. Return them all in a dictionary: {'sum': sum(arr), ...}

🧪 Test Cases

Input

f"Sum: {result['sum']}"

Expected

Sum: 28

Test case 1

Input

f"Min: {result['min']}"

Expected

Min: 1

Test case 2

Input

f"Max: {result['max']}"

Expected

Max: 9

Test case 3

Input

f"Length: {result['length']}"

Expected

Length: 6

Test case 4

Input

f"Reversed: {result['reversed']}"

Expected

Reversed: [3, 9, 1, 8, 2, 5]

Test case 5

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main.py

Hi! I'm Rex 👋

Output

Ready. Press ▶ Run or Ctrl+Enter.

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