Nbert. - 1 year ago 87

Java Question

I'm currently learning Java and I stumbled on an exercise I can't finish.

The task is to write a recursive method that takes an array and returns the difference of the greatest and smallest value.

For example

`{12, 5, 3, 8}`

`5`

`8 - 3`

`result = rightValue - leftValue`

`12-3 = 9`

It was quiet easy to implement this iterative but I have no idea how to do it recursive. Also it is part of the task to solve it by using divide and conquer.

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Answer Source

I've used divide and conquer approach here. I believe the trick here is to include middle in both the arrays that we're splitting the main array into.

/* edge cases ignored here */

```
int findMax(int[] arr, int left, int right){
if(right-left == 1) return (arr[right]-arr[left]);
int middle = left + (right-left)/2;
int max1 = findMax(arr, left, middle);
int max2 = findMax(arr, middle, right);
if(max1 >= 0 && max2 >= 0) return max1+max2;
else return Math.max(max1,max2);
}
```

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