mirror of
https://github.com/TheAlgorithms/C
synced 2024-11-25 14:59:36 +03:00
bb6c62aa62
* rename existing code as sol3
* Added naive implementation for Problem 5
* Added a solution for Euler Problem 5 with easy improvements
* rename new files
* code formatting
* update documentations
* fix docs
* updating DIRECTORY.md
Co-authored-by: buffet <niclas@countingsort.com>
Co-authored-by: github-actions <${GITHUB_ACTOR}@users.noreply.github.com>
61 lines
1.3 KiB
C
61 lines
1.3 KiB
C
/**
|
|
* \file
|
|
* \brief [Problem 5](https://projecteuler.net/problem=5) solution (Fastest).
|
|
* @details Solution is the LCM of all numbers between 1 and 20.
|
|
*
|
|
* \see Slowest: problem_5/sol1.c
|
|
* \see Slower: problem_5/sol2.c
|
|
*/
|
|
#include <stdio.h>
|
|
|
|
/** Compute [Greatest Common Divisor
|
|
* (GCD)](https://en.wikipedia.org/wiki/Greatest_common_divisor) of two numbers
|
|
* using Euclids algorithm
|
|
* @param a first number
|
|
* @param b second number
|
|
* @return GCD of `a` and `b`
|
|
*/
|
|
unsigned long gcd(unsigned long a, unsigned long b)
|
|
{
|
|
unsigned long r;
|
|
if (a > b)
|
|
{
|
|
unsigned long t = a;
|
|
a = b;
|
|
b = t;
|
|
}
|
|
while ((r = (a % b)))
|
|
{
|
|
a = b;
|
|
b = r;
|
|
}
|
|
return b;
|
|
}
|
|
|
|
/** Compute [Least Common Multiple
|
|
* (LCM)](https://en.wikipedia.org/wiki/Least_common_multiple) of two numbers
|
|
* @param a first number
|
|
* @param b second number
|
|
* @return LCM of `a` and `b`
|
|
*/
|
|
unsigned long lcm(unsigned long a, unsigned long b)
|
|
{
|
|
unsigned long long p = (unsigned long long)a * b;
|
|
return p / gcd(a, b);
|
|
}
|
|
|
|
/** Main function
|
|
* @returns 0 on exit
|
|
*/
|
|
int main(void)
|
|
{
|
|
unsigned long ans = 1;
|
|
unsigned long i;
|
|
for (i = 1; i <= 20; i++)
|
|
{
|
|
ans = lcm(ans, i);
|
|
}
|
|
printf("%lu\n", ans);
|
|
return 0;
|
|
}
|