How to compare two arrays of integers order-insensitively

Question

I want Java code that can compare in this way (for example):

<1 2 3 4>  = <3 1 2 4>
<1 2 3 4> != <3 4 1 1>

I can\'t

Answer 1

Since this is homework, I'm going to guess that a simple quadratic solution (which your original attempt is), is fine. In that case, you can do something like this:

int count(int[] nums, int x) {
    int count = 0;
    for (int num : nums) {
        if (num == x) count++;
    }
    return count;
}   
boolean equals(int[] arr1, int[] arr2) {
    if (arr1.length != arr2.length) return false;
    for (int x : arr1) {
        if (count(arr1, x) != count(arr2, x)) return false;
    }
    return true;
}

This sacrifices speed for clarity: it's obviously correct!!

Tips

• Use for-each whenever applicable; it always read to better readability
• Helper functions improve both readability and reusability!