Complete + Easy + My MergeSort

public class MyMergeSort {

/**
* @param args
*/
public static void main(String[] args) {
int[] arr = { 14, 23, 76, 32, 76, 12, 11, 90 };
mergeSort(arr , 0 ,arr.length);
for(int i = 0 ; i < arr.length ; i ++){
System.out.println(arr[i]);
}
}

public static void mergeSort(int[] input , int firstIndex , int lastIndex){
int leftHalfSize;
int rightHalfSize;
if(lastIndex > 1){
leftHalfSize = lastIndex / 2;
rightHalfSize = lastIndex - leftHalfSize;

mergeSort(input, firstIndex, leftHalfSize);
mergeSort(input, firstIndex + leftHalfSize, rightHalfSize);

merge(input , firstIndex , leftHalfSize , rightHalfSize);
}

}
public static void merge(int[] input , int firstIndex , int leftHalfSize , int rightHalfSize){
int[] temp = new int[leftHalfSize + rightHalfSize];

int[] leftArray = new int[leftHalfSize];
int[] rightArray = new int[rightHalfSize];

for(int i = 0 ; i < leftHalfSize ; i++){
leftArray[i] = input[firstIndex + i];
}
for(int j = 0 ; j < rightHalfSize ; j++){
rightArray[j] = input[firstIndex + leftHalfSize + j ];
}
int i = 0 , j = 0 ,k = 0;
for(; i < leftHalfSize && j < rightHalfSize ;){
if(leftArray[i] < rightArray[j]){
temp[k] = leftArray[i];
i++;
k++;
}else{
temp[k] = rightArray[j];
j++;
k++;
}
}
if(i < leftHalfSize){
while (i < leftHalfSize || k < leftHalfSize + rightHalfSize){
temp[k] = leftArray[i];
k++;
i++;
}
}

if(j < rightHalfSize){
while (j < rightHalfSize || k < leftHalfSize + rightHalfSize){
temp[k] = rightArray[j];
k++;
j++;
}
}
for(int m = 0 ; m < leftHalfSize + rightHalfSize ; m++){
input[firstIndex+ m ] = temp[m] ;
}
}

}

Merge Sort -> Complete Prog

public class MergeSort
{
private int a[];

public MergeSort(int b[])
{
a = b;
}
public void sort()
{
if(a.length <= 1)
return;
int first[] = new int[a.length / 2];
int second[] = new int[a.length - first.length];
for(int x = 0; x < first.length; x++)
first[x] = a[x];
for(int x = first.length, y = 0; x < a.length; x++, y++)
first[y] = a[x];
//Split the array again
MergeSort sort1 = new MergeSort(first);
MergeSort sort2 = new MergeSort(second);
sort1.sort();
sort2.sort();

merge(first, second);
}
private void merge(int first[], int second[])
{
int x = 0;
int y = 0;
int z = 0;
while(x < first.length && y < second.length)
{
if(first[x] < second[y])
{
a[z] = first[x];
x++;
}
else
{
a[z] = second[y];
y++;
}
z++;
}
//copy remaining elements to the tail of a[];
for(int i = x; i < first.length; i++)
{
a[z] = first[i];
z++;
}
for(int i = y; i < second.length; i++)
{
a[z] = second[i];
z++;
}
}
}

Merge Sort -> Merge + MergeSort

public static int[] merge(int[] a, int[] b){
int len1 = a.length;
int len2 = b.length;
int[] c = new int[len1 + len2];
int len = len1 < len2 ? len1 : len2;
int i = 0 , j = 0 , k = 0;
for(; i < len1 && j < len2 && k < len1 + len2 ; ){
if(a[i] < b[j]){
c[k] = a[i];
k++;
i++;
}else{
c[k] = b[j];
k++;
j++;
}
}

if(i < len1){
while (i != len1 || k != len1 + len2){
c[k] = a[i];
k++;
i++;
}
}

if(j < len2){
while (j != len2 || k != len1 + len2){
c[k] = b[j];
k++;
i++;
}
}

return c;
}