Udemy: Master Coding Interview - Arrays - #70

using System;

// Given two sorted arrays, merge them into a single sorted array
// Example:
//  array1: {0, 3, 4, 31}
//  array2: {4, 6, 30}
//  merged: {0, 3, 4, 4, 6, 30, 31}
class MainClass {
    static void Main() {
        int[] array1 = {0, 3, 4, 31};
        int[] array2 = {4, 6, 30};
        
        Console.WriteLine("array1 = " + toString(array1));
        Console.WriteLine("array2 = " + toString(array2));
        Console.WriteLine("merged = " + toString(merge(array2, array1)));
    }
    
    static int[] merge(int[] a1, int[] a2) {
        int[] m = new int[a1.Length + a2.Length];
        int a1CurrentIndex = 0;
        int a2CurrentIndex = 0;
        for (int i = 0; i < m.Length; i++) {
            //Console.WriteLine("a1CurrentIndex = " + a1CurrentIndex + ", a2CurrentIndex = " + a2CurrentIndex);
            
            if (a2CurrentIndex == a2.Length) {
                m[i] = a1[a1CurrentIndex];
                a1CurrentIndex++;
            } else if (a1CurrentIndex == a1.Length) {
                m[i] = a2[a2CurrentIndex];
                a2CurrentIndex++;
            } else if (a1[a1CurrentIndex] < a2[a2CurrentIndex]) {
                m[i] = a1[a1CurrentIndex];
                a1CurrentIndex++;
            } else {
                m[i] = a2[a2CurrentIndex];
                a2CurrentIndex++;
            }
            //Console.WriteLine("m = " + toString(m));
        }
        return m;
    }
    
    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;
    }
}