RecursionAndBacktracking/Reverse_array.java at main · adv11/RecursionAndBacktracking · GitHub

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packageRecursionAndBacktracking;

importjava.util.Scanner;

publicclassReverse_array {

// By two reference approach
publicstaticint[] reverseArray(int[] a, intleft, intright){
if(left >= right){
returna;
 }else {
inttemp = a[left];
a[left] = a[right];
a[right] = temp;
 }
returnreverseArray(a, left+1, right-1);
 }

// By one reference approach
publicstaticint[] reverseArray_oneReference(int[] a, intindex, intsize){
if(index >= size/2){
returna;
 }
if(index < (size - index - 1)){
inttemp = a[index];
a[index] = a[size - index - 1];
a[size - index - 1] = temp;
 }
returnreverseArray_oneReference(a, index+1, size);
 }
publicstaticvoidmain(String[] args) {
Scannersc = newScanner(System.in);
System.out.println("Enter number of test cases:");
intt = sc.nextInt();

while (t-- > 0) {
System.out.println("Enter the length of the array : ");
intsize = sc.nextInt();

int[] a1 = newint[size];
System.out.println("Enter the elements of the array:");
for (inti = 0; i < size; i++) {
a1[i] = sc.nextInt();
 }

int[] a2 = a1.clone();

System.out.println("By two reference approach");
int[] b = reverseArray(a1, 0, size - 1);
for (intele : b) {
System.out.print(ele + " ");
 }
System.out.println();


System.out.println("By one reference approach");
int[] c = reverseArray_oneReference(a2, 0, size);
for(intele : c){
System.out.print(ele + " ");
 }
System.out.println();
 }
 }
}