Q136: Ugly Numbers

// Run time: 0.080
#include <stdio.h>
const int N = 1500;

int ugly[N] = {1, 2, 3, 4, 5};
int base[3] = {2, 3, 5};
int min(int *arr);

int main()
{
    int cnt = 5;
    int tmp[3];
    int i, j;
    int index;

    while (cnt <= N)
    {
        for ( i = 0; i < 3; i++)
        {
            for ( j = 0; ugly[j] <= ugly[cnt-1]/base[i]; j++);
            tmp[i] = ugly[j]*base[i];
        }

        index = min(tmp);
        ugly[cnt++] = tmp[index];
    }

    printf("The 1500'th ugly number is %d.\n", ugly[N-1]);

    return 0;
}

int min(int *arr)
{
    int min;
    min = arr[0];

    if (min > arr[1])
    {
        min = arr[1];
        if (min > arr[2])
            return 2;
        return 1;
    }

    if (min > arr[2])
        return 2;

    return 0;
}