leetcode --- Implement strStr()

class Solution:
    def strStr(self, haystack: str, needle: str) -> int:
        if needle =="":
            return 0
        if len(haystack) == len(needle):
            if haystack == needle:
                return 0
            else:
                return -1
        haystack = list(haystack)
        needle = list(needle)
        if len(haystack) <len(needle):
            return -1
        len2=len(needle)
        for i in range(len(haystack)):
            p=0
            if needle[0] ==haystack[i]:
                h=i
                j=0
                while (j<len2) and (i<len(haystack)) and (needle[j]==haystack[i]) and (p<len2) :
                    print(i)
                    print(j)
                    i=i+1
                    j=j+1
                    p=p+1
                if p == len2:
                    return h
                    
        return -1