Merge Sort Hack
class StringArr {
// Merges two subarrays of arr[].
// First subarray is arr[l..m]
// Second subarray is arr[m+1..r]
void merge(String arr[], int l, int m, int r) {
// Find the sizes of two subarrays to be merged
int n1 = m - l + 1;
int n2 = r - m;
/* Create temp arrays */
String[] L = new String[n1];
String[] R = new String[n2];
/* Copy data to temp arrays */
for (int i = 0; i < n1; ++i)
L[i] = arr[l + i];
for (int j = 0; j < n2; ++j)
R[j] = arr[m + 1 + j];
/* Merge the temp arrays */
// Initial indexes of first and second subarrays
int i = 0, j = 0;
// Initial index of merged subarray array
int k = l;
while (i < n1 && j < n2) {
if (L[i].compareTo(R[j]) <= 0) {
//use of compareTo for strings
arr[k] = L[i];
i++;
} else {
arr[k] = R[j];
j++;
}
k++;
}
/* Copy remaining elements of L[] if any */
while (i < n1) {
arr[k] = L[i];
i++;
k++;
}
/* Copy remaining elements of R[] if any */
while (j < n2) {
arr[k] = R[j];
j++;
k++;
}
}
// Main function that sorts arr[l..r] using
// merge()
void sort(String[] arr, int l, int r) {
if (l < r) {
int m = l + (r - l) / 2;
sort(arr, l, m);
sort(arr, m + 1, r);
merge(arr, l, m, r);
}
}
/* A utility function to print array of size n */
static void printArray(String[] arr) {
int n = arr.length;
for (int i = 0; i < n; ++i)
System.out.print(arr[i] + " ");
System.out.println();
}
// tester method
public static void main(String args[]) {
String[] arr = { "f", "c", "e", "d", "b", "a" };
System.out.println("Given Array");
printArray(arr);
Main ob = new Main();
ob.sort(arr, 0, arr.length - 1);
System.out.println();
System.out.println("Sorted array");
printArray(arr);
}
}
StringArr.main(null);