I have been given the function below in pseudocode and I am trying to translate it to JS, but I keep getting an infinity loop.
Thanks zord, mid fixed the recursion issue. Now I get the wrong sum, any suggestions?
What am I doing wrong?
function SUM(arr, left, right){
if(left > right){
return 0
}
else if(left == right){
return arr[left]
}
mid = Math.floor((left + right) / 2);
lsum = SUM(arr,left,mid);
rsum = SUM(arr,mid+1,right);
return lsum + rsum
}
arr = [1,2,3,4,5]
left = 0;
right = arr.length - 1;
console.log(SUM(arr, left, right));
Thanks!
mid should be halfway between left and right:
mid = Math.floor((left + right) / 2);
Also, you need to make your variables block scoped as VLAZ mentioned. Otherwise they will be global, and overwritten by different runs of the function.
const mid = Math.floor((left + right) / 2);
const lsum = SUM(arr, left, mid);
const rsum = SUM(arr, mid + 1, right);