Find the largest product of any two numbers in a list

Problem statement: Find the largest product of any two numbers in a list
Input - a list of numbers
Output - the largest product of any 2 numbers in the list
e.g. - [1 7 3 4 2 6 5]  => 42

1. public class ProductOfLargestNum {
2. public static void main(String[] args) {
3. 
   
4. int a[] = { 1, 7, 3, 4, 2, 6, 5 };
5. int temp;
6. /*
7. * logic is to sort the list first then get last and last but one
8. * element and do the product
9. */
10.    // bubble sort algorithm
11. for (int i = 0; i < a.length; i++) {
12. for (int j = 0; j < a.length - 1; j++) {
13. if (a[j] > a[j + 1]) {
14. temp = a[j];
15. a[j] = a[j + 1];
16. a[j + 1] = temp;
17. }
18. }
19. }
20. System.out.println("list after sorting");
21. for (int i : a) {
22. System.out.print(i + " ");
23. }
24. int last = a[a.length - 1];
25. int lastButOne = a[a.length - 2];
26. System.out.println();
27. System.out.println(last * lastButOne);
28. }
29. }

Output:

list after sorting

1 2 3 4 5 6 7 

42

Write a program to sort numeric array !!

// Method-I:

1. public class SortIntegerArrayAlgorithm {
2. public static void main(String[] args) {
3. int a[] = { 2, 3, 4, 5, 22, 13, 5, 3 };
4. int temp;
5. for (int i = 0; i < a.length; i++) {
6. for (int j = 0; j < a.length - 1; j++) {
7. if (a[j] > a[j + 1]) {
8. temp = a[j];
9. a[j] = a[j + 1];
10. a[j + 1] = temp;
11. }
12. }
13. }
14. for (int i : a) {
15. System.out.print(i + " ");
16. }
17. }
18. }

Output: 2 3 3 4 5 5 13 22
Note: This is also called Bubble sort algorithm.

// Method-II:

1. public class SortIntArrayAlgorithm {
2. 
   
3. public static void main(String[] args) {
4. int a[] = { 1, 43, 4, 43, 33, 2, 2, 5, 5, 5, 5, 33, 777 };
5. Arrays.sort(a);
6. for (int i : a) {
7. System.out.print(i + " ");
8. }
9. }
10. }

Output: 1 2 2 4 5 5 5 5 33 33 43 43 777 

Note: Sorting has been done using pre-defined method not our own algorithm.