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Python Program for Find remainder of array multiplication divided by n
• Difficulty Level : Basic
• Last Updated : 23 Mar, 2021

Given multiple numbers and a number n, the task is to print the remainder after multiply all the number divide by n.
Examples:

```Input : arr[] = {100, 10, 5, 25, 35, 14},
n = 11
Output : 9
100 x 10 x 5 x 25 x 35 x 14 = 61250000 % 11 = 9```

Naive approach: First multiple all the numbers then take % by n then find the remainder, But in this approach, if the number is maximum of 2^64 then it gives the wrong answer.
Approach that avoids overflow : First take a remainder or individual number like arr[i] % n. Then multiply the remainder with the current result. After multiplication, again take the remainder to avoid overflow. This works because of the distributive properties of modular arithmetic. ( a * b) % c = ( ( a % c ) * ( b % c ) ) % c

## Python3

 `# Python3 program to``# find remainder when``# all array elements``# are multiplied.` `# Find remainder of arr * arr``# * .. * arr[n-1]``def` `findremainder(arr, lens, n):``    ``mul ``=` `1` `    ``# find the individual``    ``# remainder and``    ``# multiple with mul.``    ``for` `i ``in` `arr:``        ``mul ``=` `mul ``*` `(i ``%` `n)` `    ``return` `mul ``%` `n`  `# Driven code``arr ``=` `[``100``, ``10``, ``5``, ``25``, ``35``, ``14``]``lens ``=` `len``(arr)``n ``=` `11` `# print the remainder``# of after multiple``# all the numbers``print``(findremainder(arr, lens, n))` `# This code is contributed by "rishabh_jain".`

Output:

`9`

Please refer complete article on Find remainder of array multiplication divided by n for more details!

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