Problem: Given are two strings s and t consisting of lowercase English letters. Determine if the number of non-negative integers i satisfying the following condition is finite, and find the maximum value of such i if the number is finite.    * There exists a non-negative integer j such that the concatenation of i copies of t is a substring of the concatenation of j copies of s.

Submission attempts (in order):
import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

S = np.array(list(readline().rstrip()),np.int64)
T = np.array(list(readline().rstrip()),np.int64)

LS = len(S); LT = len(T)
LSext = LS + LT
LSext += (-LSext) % LS
Sext = np.tile(S,LSext//LS)

def cumprod(arr,MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr,Lsq**2).reshape(Lsq,Lsq)
    for n in range(1,Lsq):
        arr[:,n] *= arr[:,n-1]; arr[:,n] %= MOD
    for n in range(1,Lsq):
        arr[n] *= arr[n-1,-1]; arr[n] %= MOD
    return arr.ravel()[:L]

U = 10**6 + 100
base = 1234
MOD = 10**9 + 9
x = np.full(U,base,dtype=np.int64); x[0] = 1
power = cumprod(x,MOD)
x = np.full(U,pow(base,MOD-2,MOD),dtype=np.int64); x[0] = 1
power_inv = cumprod(x,MOD)

def RollingHash(S):
    return (S * power[:len(S)] % MOD).cumsum() % MOD

Sext_hash = RollingHash(Sext)
T_hash = RollingHash(T)[-1]


x = Sext_hash[LT-1:LS+LT-1]
x[1:] -= Sext_hash[:LS-1]
x *= power_inv[:LS]; x %= MOD


import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

S = np.array(list(readline().rstrip()),np.int64)
T = np.array(list(readline().rstrip()),np.int64)

LS = len(S); LT = len(T)
LSext = LS + LT
LSext += (-LSext) % LS
Sext = np.tile(S,LSext//LS)

def cumprod(arr,MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr,Lsq**2).reshape(Lsq,Lsq)
    for n in range(1,Lsq):
        arr[:,n] *= arr[:,n-1]; arr[:,n] %= MOD
    for n in range(1,Lsq):
        arr[n] *= arr[n-1,-1]; arr[n] %= MOD
    return arr.ravel()[:L]

U = 2*10**6
base = 1234
MOD = 10**9 + 9
x = np.full(U,base,dtype=np.int64); x[0] = 1
power = cumprod(x,MOD)
x = np.full(U,pow(base,MOD-2,MOD),dtype=np.int64); x[0] = 1
power_inv = cumprod(x,MOD)

def RollingHash(S):
    return (S * power[:len(S)] % MOD).cumsum() % MOD

Sext_hash = RollingHash(Sext)
T_hash = RollingHash(T)[-1]


x = Sext_hash[LT-1:LS+LT-1]
x[1:] -= Sext_hash[:LS-1]
x *= power_inv[:LS]; x %= MOD


import sys
read = sys.stdin.buffer.read
readline = sys.stdin.buffer.readline
readlines = sys.stdin.buffer.readlines

import numpy as np

S = np.array(list(readline().rstrip()),np.int64)
T = np.array(list(readline().rstrip()),np.int64)

LS = len(S); LT = len(T)
LSext = LS + LT
LSext += (-LSext) % LS
Sext = np.tile(S,LSext//LS)

def cumprod(arr,MOD):
    L = len(arr); Lsq = int(L**.5+1)
    arr = np.resize(arr,Lsq**2).reshape(Lsq,Lsq)
    for n in range(1,Lsq):
        arr[:,n] *= arr[:,n-1]; arr[:,n] %= MOD
    for n in range(1,Lsq):
        arr[n] *= arr[n-1,-1]; arr[n] %= MOD
    return arr.ravel()[:L]

U = 2*10**6
MOD = 10 ** 9 + 993
base = 123450
x = np.full(U,base,dtype=np.int64); x[0] = 1
power = cumprod(x,MOD)
x = np.full(U,pow(base,MOD-2,MOD),dtype=np.int64); x[0] = 1
power_inv = cumprod(x,MOD)

def RollingHash(S):
    return (S * power[:len(S)] % MOD).cumsum() % MOD

Sext_hash = RollingHash(Sext)
T_hash = RollingHash(T)[-1]


x = Sext_hash[LT-1:LS+LT-1].copy()
x[1:] -= Sext_hash[:LS-1]
x *= power_inv[:LS]; x %= MOD


INF = LS+100
cnt = [INF] * LS
stack = np.where(x!=T_hash)[0].tolist()
for x in stack:
    cnt[x] = 0
while stack:
    x = stack.pop()
    y = (x-LT)%LS
    if cnt[y] == INF:
        cnt[y] = cnt[x] + 1
        stack.append(y)

answer = max(cnt)
if answer == INF:
    answer = -1
print(answer)

Verdicts: Runtime Error

Wrong Answer

Accepted