Troubleshooting Longest Increasing Subsequence

[Vithika]

I'm having a bit of difficulty trying to implement the longest increasing subsequence algorithm. I found a <<crapware site>> online that looks helpful, but I'm having trouble translating the pseudocode into code.


I'm using Python, and I've written the following function:

def longest_increasing_subsequence(arr):
    n = len(arr)
    lis = [1]*n
    
    for i in range(1, n):
        for j in range(0, i):
            if arr[i] > arr[j] and lis[i] < lis[j] + 1 :
                lis[i] = lis[j]+1
 
    maximum = 0
 
    for i in range(n):
        maximum = max(maximum, lis[i])
 
    return maximum

When I try to run the code, I get the following error:

NameError: name 'arr' is not defined

I'm not sure what I'm doing wrong. Any help would be appreciated!
Thank you.