return value problem

[laxbro]

I need to make the mergeSort method return the number of compares and swaps it did but I don't know what I am doing wrong. Still new to java so it's probable simple but I need help. There are some comments from my teacher in their

public static int[] mergeSort(int[] arr) {
		
		for (int blockSize=1; blockSize<arr.length; blockSize*=2) {
		
			for (int leftIndex=0; leftIndex<arr.length; leftIndex+=2*blockSize) {
				// And make this method also return compares and swaps
				merge(arr, leftIndex, leftIndex+blockSize, leftIndex+2*blockSize);
			}
		}
		int[] results = new int [3];
		results[ARRAY_SIZE]=arr.length;
		results[COMPARES]=compares;
		results[SWAPS]=swaps;
		return results;
	}
	// Change the return type here, so you can return compares and swaps from it
	public static int[] merge(int[] sourceArray, int leftStart, int middleIndex, int rightEnd){
		int compares=0, swaps=0;
		if (middleIndex>=sourceArray.length) {
			// In this case, return 0 compares, and 0 swaps
			int[] results = new int [3];
			results[COMPARES]=compares;
			results[SWAPS]=swaps;
			return results;
			
		}
		if (rightEnd>=sourceArray.length) {
			rightEnd=sourceArray.length;
		}
		int[] tempArray=new int[sourceArray.length];
		for (int i=leftStart; i<rightEnd; i++) {
			tempArray[i]=sourceArray[i];
		}
		int leftIndex=leftStart;
		int rightIndex=middleIndex;
		int currentCopyIndex=leftStart;
		while(leftIndex<middleIndex && rightIndex<rightEnd) {
			// Here is your compare
			compares++;
			if (tempArray[leftIndex]<tempArray[rightIndex]) {
				// Here is a swap
				swaps++;
				sourceArray[currentCopyIndex]=tempArray[leftIndex];
				leftIndex++;
			} else {
				// Here is another swap
				swaps++;
				sourceArray[currentCopyIndex]=tempArray[rightIndex];
				rightIndex++;			
			}
			currentCopyIndex++;
		}
		while (leftIndex<middleIndex) {
			// This too is a swap
			swaps++;
			sourceArray[currentCopyIndex]=tempArray[leftIndex];
			leftIndex++;	
			currentCopyIndex++;
		}
		while (rightIndex<rightEnd) {
			// And this is a swap
			swaps++;
			sourceArray[currentCopyIndex]=tempArray[rightIndex];
			rightIndex++;	
			currentCopyIndex++;
		}
		int[] results = new int [3];
		results[COMPARES]=compares;
		results[SWAPS]=swaps;
		return results;
	}

[quad64bit]

one thing that will make it a LOT easier is if you break your swap and compare statements out into separate methods. That way, you can increment your counter every time the method is called!

[laxbro]

It has to be done this way for the test program to work

[Tolls]

No it doesn't.
Your test program will simply be calling the merge method (presumably).
Whether that merge method then calls other methods should be irrelevant to it.

Unless you have been given a very silly test program.