Udemy: Master Coding Interview - Merge Sort - #175

using System;

class MainClass {
    static void Main() {
        int[] numbers = {99, 44, 6, 2, 1, 5, 63, 87, 283, 4, 0};
        //6, 8, 7
        //6, 8, 8
        Console.WriteLine(ToString(numbers));
        numbers = MergeSort(numbers);
        Console.WriteLine(ToString(numbers));
    }
    
    public static int[] MergeSort(int[] array) {
        if (array.Length == 1) {
            return array;
        }
        
        // Split Array into right and left
        int[] left = new int[array.Length / 2];
        int[] right = new int[array.Length - array.Length / 2];
        for (int i = 0; i < array.Length; i++) {
            if (i < array.Length / 2) {
                left[i] = array[i];
            } else {
                right[i - array.Length / 2] = array[i];
            }
        }
        
        return Merge(MergeSort(left), MergeSort(right));
    }
    
    public static int[] Merge(int[] left, int[] right) {
        int[] merged = new int[left.Length + right.Length];
        int index = 0;
        int leftIndex = 0;
        int rightIndex = 0;
        while (leftIndex < left.Length || rightIndex < right.Length) {
            if (leftIndex == left.Length) {
                merged[index++] = right[rightIndex++];
            } else if (rightIndex == right.Length) {
                merged[index++] = left[leftIndex++];
            } else {
                if (left[leftIndex] < right[rightIndex]) {
                    merged[index++] = left[leftIndex++];
                } else {
                    merged[index++] = right[rightIndex++];
                }
            }
        }
        return merged;
    }
    
    public static string ToString(int[] array) {
        string s = "{";
        for (int i = 0; i < array.Length; i++) {
            if (i > 0) {
                s += ", ";
            }
            s += array[i];
        }
        s += "}";
        return s;
    }
}