Puzzle 8-13-2008 (answers)

[Steven Schveighoffer]

I actually found these quite easy :)

BTW, to denote squared, you should use a^2, the way you wrote the third 
problem had me very confused for a while :)  I thought there was a 
constraint like: a*10 + 2 + b*10 + 2 == c * 10 + 2.

import tango.io.Stdout;

void prob1()
{
    int s = 0;
    for(int i = 1; i < 1000; i++)
    {
        if(i % 3 == 0 || i % 5 == 0)
            s += i;
    }
    Stdout(s).newline;
}

void prob2()
{
    auto target= 600_851_475_143;
    for(ulong i = 3; i * i < target; i++)
        if(target % i == 0)
        {
            Stdout(i).newline;
            return;
        }
    Stdout(target)(" is prime!").newline;
}

void prob3()
{
    for(int i = 1; i < 1000; i++)
        for(int j = i; i + j < 1000; j++)
        {
            int k = 1000 - i - j;
            if(k < j)
                break;

            if(i * i + j * j == k * k)
            {
                Stdout(i, j, k).newline;
            }
        }
}

void main()
{
    prob1;
    prob2;
    prob3;
}

Answers:
233168
71
200, 375, 425

execution time:

real    0m0.004s
user    0m0.002s
sys     0m0.002s