// Marty Stepp, CSE 142, Spring 2010
// This program shows methods to merge elements of 2/3 arrays,
// and return the result.
// Its purpose is to demonstrate returning arrays.

import java.util.*;

public class Merge {
    public static void main(String[] args) {
        int[] a3 = {12, 34, 56};
        int[] a4 = {20, 50, 80, -1, 90};
        int[] big = merge(a3, a4);
        System.out.println(Arrays.toString(big));

        int[] a5 = {4, 19, -2, 6};
        int[] big3 = merge3(a3, a4, a5);
        System.out.println(Arrays.toString(big3));
    }
    
    // Returns a new array containing all elements of a1
    // followed by all elements of a2.
    public static int[] merge(int[] a1, int[] a2) {
        int[] result = new int[a1.length + a2.length];
        for (int i = 0; i < a1.length; i++) {
            result[i] = a1[i];
        }
        for (int i = 0; i < a2.length; i++) {
            result[i + a1.length] = a2[i];
        }
        return result;
    }
    
    // Returns a new array containing all elements of a1, a2, and a3.
    public static int[] merge3(int[] a1, int[] a2, int[] a3) {
        int[] result = new int[a1.length + a2.length + a3.length];

        for (int i = 0; i < a1.length; i++) {
            result[i] = a1[i];
        }
        for (int i = 0; i < a2.length; i++) {
            result[a1.length + i] = a2[i];
        }
        for (int i = 0; i < a3.length; i++) {
            result[a1.length + a2.length + i] = a3[i];
        }

        return result;
    }

    // Shorter version that calls merge.
    public static int[] merge3shorter(int[] a1, int[] a2, int[] a3) {
        return merge(merge(a1, a2), a3);
    }
}