Problem #43 says:
The number, 1406357289, is a 0 to 9 pandigital number because
it is made up of each of the digits 0 to 9 in some order, but it also
has a rather interesting sub-string divisibility property.
Let d_(1) be the 1^(st) digit, d_(2) be the 2^(nd) digit, and so on.
In this way, we note the following:
* d_(2)d_(3)d_(4)=406 is divisible by 2
* d_(3)d_(4)d_(5)=063 is divisible by 3
* d_(4)d_(5)d_(6)=635 is divisible by 5
* d_(5)d_(6)d_(7)=357 is divisible by 7
* d_(6)d_(7)d_(8)=572 is divisible by 11
* d_(7)d_(8)d_(9)=728 is divisible by 13
* d_(8)d_(9)d_(10)=289 is divisible by 17
Find the sum of all 0 to 9 pandigital numbers with this property.This Problem along with problem #41 were done as battery test for my new computer and use a brute force method to solve the problem with little or no optimization. Therefor they take a long time to run. I will probably return at some point and see if i cannot speed things up. Until then Solution in C#/mono.
using System;
using System.Diagnostics;
using System.Collections;
using System.Collections.Generic;
using System.Text;
namespace ProjectEuler
{
class Program
{
static void Main(string[] args)
{
Stopwatch sw = new Stopwatch();
sw.Start();
long Answer = 0;
long Stepper = 1000000000;
long Max = 9999999999;
while (Stepper <= Max)
{
if (CheckNum(Stepper))
{
Answer += Stepper;
}
if (Stepper % 5000000 == 0)
{
Console.WriteLine(Stepper.ToString() +
" :: " + (((float)Stepper / (float)Max) * (float)100).ToString());
}
Stepper++;
}
Console.WriteLine(Answer);
sw.Stop();
Console.WriteLine(sw.Elapsed);
Console.ReadLine();
}
static bool CheckNum(long num)
{
if (num.ToString().Length != 10)
{
return false;
}
if (IsPandigital(num) != 1)
{
return false;
}
string Num = num.ToString();
int d1 = int.Parse(Num[0].ToString());
int d2 = int.Parse(Num[1].ToString());
int d3 = int.Parse(Num[2].ToString());
int d4 = int.Parse(Num[3].ToString());
int d5 = int.Parse(Num[4].ToString());
int d6 = int.Parse(Num[5].ToString());
int d7 = int.Parse(Num[6].ToString());
int d8 = int.Parse(Num[7].ToString());
int d9 = int.Parse(Num[8].ToString());
int d10 = int.Parse(Num[9].ToString());
if (((d2 * 100) + (d3 * 10) + d4) % 2 != 0)
{
return false;
}
if (((d3 * 100) + (d4 * 10) + d5) % 3 != 0)
{
return false;
}
if (((d4 * 100) + (d5 * 10) + d6) % 5 != 0)
{
return false;
}
if (((d5 * 100) + (d6 * 10) + d7) % 7 != 0)
{
return false;
}
if (((d6 * 100) + (d7 * 10) + d8) % 11 != 0)
{
return false;
}
if (((d7 * 100) + (d8 * 10) + d9) % 13 != 0)
{
return false;
}
if (((d8 * 100) + (d9 * 10) + d10) % 17 != 0)
{
return false;
}
return true;
}
static long IsPandigital(long i)
{
char[] I = i.ToString().ToCharArray();
long[] counters = new long[9] { 0, 0, 0, 0, 0, 0, 0, 0, 0 };
foreach (char c in I)
{
switch (c)
{
case '1':
counters[0] += 1;
break;
case '2':
counters[1] += 1;
break;
case '3':
counters[2] += 1;
break;
case '4':
counters[3] += 1;
break;
case '5':
counters[4] += 1;
break;
case '6':
counters[5] += 1;
break;
case '7':
counters[6] += 1;
break;
case '8':
counters[7] += 1;
break;
case '9':
counters[8] += 1;
break;
}
}
foreach (long Check in counters)
{
if (Check > 1)
return -1;
if (Check == 0)
return 0;
}
return 1;
}
}
}