PA1 - úkol 4.1 (Vláčky na nádraží)

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <limits.h>

unsigned int gcd( unsigned int a, unsigned int b );
unsigned int lcm( unsigned int a, unsigned int b );

int main ( int argc, char * argv[] )
 {
    int n, i, h, m;
    unsigned int meet = 1;
    unsigned int trainInt[20];

    puts( "Zadejte pocet vlaku:" );
    if ( scanf( "%d", &n ) != 1 || n < 1 || n > 20 )
     {
        puts ( "Nespravny vstup." );
        return 1;
     }

    for ( i = 0; i < n; i++ )
     {
        printf( "Interval vlaku %d:\n", i + 1 );
        if ( scanf( "%d:%d", &h, &m ) != 2 || m > 59 || h + m == 0 || h < 0 || m < 0 )
         {
            puts ( "Nespravny vstup." );
            return 1;
         }
        trainInt[i] = 60 * h + m;
     }

    for ( i = 0; i < n; i++ )
     {
        if ( lcm( meet, trainInt[i] ) == UINT_MAX )
         {
            puts( "Vysledek mimo rozsah datoveho typu." );
            return 0;
         }
        meet = lcm( meet, trainInt[i] );
     }

    printf( "Vsechny vlaky se potkaji za: %d:%.2d\n", meet / 60, meet % 60);

    puts( "Mezitim projede:" );
    for ( i = 0; i < n; i++ )
     {
        printf( "* vlak %d: %dx", i+1, ( meet / trainInt[i] ) - 1 );
        if ( i < n - 2 )
            printf( ",\n" );
        if ( i == n - 2 )
            printf( " a\n" );
        if ( i == n - 1)
            printf( ".\n" );
     }

    return 0;
 }

unsigned int gcd( unsigned int a, unsigned int b )
 {
    unsigned int tmp;
    while ( b != 0 )
     {
        tmp = a;
        a = b;
        b = tmp % b;
     }
    return a;
 }

unsigned int lcm( unsigned int a, unsigned int b )
 {
    unsigned long int x = ( unsigned long int ) a * b;
    if ( x > UINT_MAX )
        return UINT_MAX;
    return (a * b) / gcd( a, b );
 }