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Can all numbers of array be made equal

Learn how to solve the 'Can all numbers of array be made equal' problem. This detailed resource details brute force and optimized approaches.

Problem Statement

Easy

Write a function can_make_equal(arr) that determines if all elements of the array can be made equal by repeatedly adding or subtracting any element from another. This is possible if and only if the total sum of the array is divisible by the length of the array (i.e., the mean is an integer). Return True if possible, False otherwise. Note: a simpler interpretation — if we can redistribute values freely, we can always make them equal when the sum is divisible by length.

Constraints
  • 1 <= len(arr) <= 10^5
  • -10^6 <= arr[i] <= 10^6

Examples

Example 1
Input
arr = [1, 1, 1]
Output
True
Explanation

All elements are already equal.

Example 2
Input
arr = [1, 2, 3]
Output
True
Explanation

Sum = 6, length = 3. 6/3 = 2. We can make all elements 2.

Example 3
Input
arr = [1, 2, 4]
Output
False
Explanation

Sum = 7, length = 3. 7/3 is not an integer, so we cannot make all equal.

Need a Hint?
Use simple arithmetic operators (like modulo `%`, division `//`), conditional checks, or loops to inspect number properties.
Edge Cases to Watch
  • Empty list or null input variables
  • Single item lists/arrays
  • Extremely large input bounds causing integer or stack overflow

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