🔒 sliding window help

[loud horizon]

given two strings s1 and pattern
find how many substrings in s that is equal to string pattern

i knew the algo for this is sliding window, but im havin a difficult time coding it up, any help is appriciated.

def sliding(s1):
            # sliding window
            l, r = 0, 0
            i = 0
            count = 0
        
            print(s1)
            while r < len(s1):
                if i + 1 == len(pattern):
                    count += 1
                    i = 0
                    
                char = s1[r]
                # if valid char
                if i + 1 < len(pattern) and char == pattern[i]:
                    # proceed with this, it is good
                    i += 1

                # not valid char
                else:
                    # check if i + 1 == len(pattern) cuz if so it is 1 cell found
                    i = 0
                    l += 1
                    while l < r and s1[l] != pattern[i]:
                        l += 1

                print(s1[r],r, l)
                r += 1
                        
            return count

[solid flower]

@loud horizon

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[loud horizon]

https://paste.pythondiscord.com/DT2Q

[patent garden]

it looks like you never define pattern is there any more code you have?

[loud horizon]

ah yes its input fields

[patent garden]

also, do you get any errors? or does the program just not work?

[loud horizon]

return wrong answer

in this case

s1 = "aaccbbbcaabacaacaacc"
pattern = "abaca"

it should return 1 but 0 is returned

[patent garden]

there's probably some small detail in your algorithm that's going wrong. I'd try to look at it step by step and identify exactly where it's different from expected

https://pythontutor.com/visualize.html is a great website for that

[loud horizon]

its in the letter "a" thats incorrect in string s1 before the correct substring

[loud horizon]

ill take a look

ahhhhhh i see

i shouldn't move the r pointer there

wait whats the point of 2 pointers here

[solid flower]

Python help channel closed for inactivity

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