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mergeSort.java
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mergeSort.java
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import java.util.Random;
public class mergeSort{
private int[] input;
private static Random generator = new Random();
public mergeSort(int size){
input = new int[size];
for ( int i = 0; i < size ; i++ ){
input[i] = 10 + generator.nextInt(90);
System.out.println(Integer.toString(input[i]));
}
}
public mergeSort(int[] a){
this.input = a;
}
public void sort(){
sortArray(0, input.length-1);
}
public void sortArray(int low, int high){
if ((high - low) >= 1) {
int middle1 = (high + low)/2;
System.out.println(input[middle1]);
int middle2 = middle1 + 1;
System.out.println("split" + subarray(low, high));
System.out.println(" " + subarray(low, middle1));
System.out.println(" " + subarray(middle2, high));
sortArray(low, middle1);
sortArray(middle2, high);
merge(low, middle1, middle2, high);
}
}
public void merge(int low, int middle1, int middle2, int high){
int leftIndex = low;
int rightIndex = middle2;
int combineIndex = low;
int[] combine = new int[input.length];
System.out.println( "merge: " + subarray( low, middle1 ) );
System.out.println( " " + subarray( middle2,high ) );
while(leftIndex <=middle1 && rightIndex <= high){
if (input[leftIndex] <= input[rightIndex]){
combine[combineIndex++] = input[leftIndex++];
}
else{
combine[combineIndex++] = input[rightIndex++];
}
}
if (leftIndex == middle2){
while(rightIndex <= high){
combine[combineIndex++] = input[rightIndex++];
}
}
else{
while(leftIndex <= middle1){
combine[combineIndex++]= input[leftIndex++];
}
}
for (int i = low; i<=high;i++){
input[i] = combine[i];
System.out.println( " " + subarray( low, high ) );
System.out.println();
}
}
public String subarray( int low, int high )
{
StringBuffer temporary = new StringBuffer();
// output spaces for alignment
for ( int i = 0; i < low; i++ )
temporary.append( " " );
// output elements left in array
for ( int i = low; i <= high; i++ )
temporary.append( " " + input[ i ] );
return temporary.toString();
} // end method subarray
// method to output values in array
public String toString()
{
return subarray( 0, input.length - 1 );
} // end method toString
public static void main(String[] args){
mergeSort m = new mergeSort(8);
m.sort();
}
}