How to compute mod of a big number?
Given a big number ‘num’ represented as string and an integer x, find value of “num % x” or “num mod x”. Output is expected as an integer.
Examples :
Input: num = "12316767678678", a = 10 Output: num (mod a) ≡ 8
The idea is to process all digits one by one and use the property that xy (mod a) ≡ ((x (mod a) * y) (mod a)). Below is the implementation.
Thanks to utkarsh111 for suggesting the below solution.
C++
// C++ program to compute mod of a big number represented // as string #include<iostream> using namespace std; // Function to compute num (mod a) int mod(string num, int a) { // Initialize result int res = 0; // One by one process all digits of 'num' for (int i = 0; i < num.length(); i++) res = (res*10 + (int)num[i] - '0') %a; return res; } // Driver program int main() { string num = "12316767678678"; cout << mod(num, 10); return 0; } |
Java
// Java program to compute mod of a big // number represented as string import java.io.*; class GFG { // Function to compute num (mod a) static int mod(String num, int a) { // Initialize result int res = 0; // One by one process all digits of 'num' for (int i = 0; i < num.length(); i++) res = (res * 10 + (int)num.charAt(i) - '0') % a; return res; } // Driver program public static void main(String[] args) { String num = "12316767678678"; System.out.println(mod(num, 10)); } } // This code is contributed by vt_m. |
Python3
# program to compute mod of a big number # represented as string # Function to compute num (mod a) def mod(num, a): # Initialize result res = 0 # One by one process all digits # of 'num' for i in range(0, len(num)): res = (res * 10 + int(num[i])) % a; return res # Driver program num = "12316767678678"; print(mod(num, 10)) # This code is contributed by Sam007 |
C#
// C# program to compute mod of a big // number represented as string using System; public class GFG { // Function to compute num (mod a) static int mod(String num, int a) { // Initialize result int res = 0; // One by one process all // digits of 'num' for (int i = 0; i < num.Length; i++) res = (res * 10 + (int)num[i]- '0') % a; return res; } // Driver code public static void Main() { String num = "12316767678678"; Console.WriteLine(mod(num, 10)); } } // This code is contributed by Sam007 |
PHP
<?php // PHP program to compute mod // of a big number represented // as string // Function to compute num (mod a) function mod($num, $a) { // Initialize result $res = 0; // One by one process // all digits of 'num' for ($i = 0; $i < $r = strlen($num); $i++) $res = ($res * 10 + $num[$i] - '0') % $a; return $res; } // Driver Code $num = "12316767678678"; echo mod($num, 10); // This code is contributed by ajit ?> |
Output :
8
Please write comments if you find anything incorrect, or you want to share more information about the topic discussed above
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