Rabin Karp ALgorithm Pattern Search

#User function Template for python3
'''
Gives 0 to 26
'''
def get(x):
    return ord(x)-ord('a')
'''
Compute hash value for given string with base 26.
'''
def hash(x):
    ans=0
    for i in x:
        ans=(ans*26+get(i))%mod
    return ans
'''
mod:largest prime number known
tar:target hash value
fp:first power=26**(n-1) . This can be used just to avoid writing firts power many times.
patt:pattern to search
s:Given string
First calculate hash value of whole pattern ans store it in tar.
Next now caluculate has value for first len(patt)-1 chars.
Then find rolling has from n-1 to len(s).
'''
class Solution:
    def search(self, s, patt):
        mod,ans=10**9+7,ans
        tar=hash(s)
        n=len(s)
        temp=hash(patt[:n-1])
        fp=26**(n-1)

        for i in range(n-1,len(patt)):
            temp=(temp*26+get(patt[i]))%mod
            if temp==tar and patt[i+1-n:i+1]==s:
                ans.append(i+1-n)#(i+1-n) because you can take an example patt="san" and s="sandeep" so to add 0 to ans you have to do i+1-n
            temp=(temp-fp*get(patt[i+1-n]))%mod

        return ans