package Visualizer.Sorts;

import Visualizer.SortingVisualizer;

public class MergeSort implements Runnable{

public void run() {

Integer[] toBeSorted = SortingVisualizer.toBeSorted;

inPlaceSort(toBeSorted);

SortingVisualizer.isSorting=false;

}

public void inPlaceSort ( Integer[] x )

{ inPlaceSort (x, 0, x.length-1); }

private void inPlaceSort ( Integer[] x, int first, int last )

{

int mid, lt, rt;

int tmp;

if ( first >= last ) return;

mid = (first + last) / 2;

inPlaceSort (x, first, mid);

inPlaceSort (x, mid+1, last);

lt = first; rt = mid+1;

// One extra check: can we SKIP the merge?

if ( x[mid] <= x[rt])

return;

while (lt <= mid && rt <= last)

{

// Select from left: no change, just advance lt

if ( x[lt] <= x[rt])

lt++;

// Select from right: rotate [lt..rt] and correct

else

{

tmp = x[rt]; // Will move to [lt]

for (int i = rt-lt;i>0; i--){

x[lt+i] = x[lt+i-1];

}

x[lt] = tmp;

// EVERYTHING has moved up by one

lt++; mid++; rt++;

}

SortingVisualizer.frame.reDrawArray(x, mid, rt, lt);

try {

Thread.sleep(SortingVisualizer.sleep);

} catch (InterruptedException e) {

e.printStackTrace();

}

}

// Whatever remains in [rt..last] is in place

}

}