Project Euler Problem 30

Problem 30

08 November 2002

Surprisingly there are only three numbers that can be written as the sum of fourth powers of their digits:

1634 = 1⁴ + 6⁴ + 3⁴ + 4⁴
8208 = 8⁴ + 2⁴ + 0⁴ + 8⁴
9474 = 9⁴ + 4⁴ + 7⁴ + 4⁴

As 1 = 1⁴ is not a sum it is not included.

The sum of these numbers is 1634 + 8208 + 9474 = 19316.

Find the sum of all the numbers that can be written as the sum of fifth powers of their digits.

Answer: 443839

C#

 

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Numerics;

namespace ConsoleApplication1 {
    class Program {
        static void Main(string[] args) {
            Console.WriteLine(Enumerable.Range(10, 500000)
                .Where(n => n.ToString().Select(x => x - '0')
                .Select(x => x * x * x * x * x).Sum() == n)
                .Sum());
        }
    }
}

 

Racket

 

#lang racket
(define (number->digits x)
  (map (lambda (x) (- (char->integer x)
                      (char->integer #\0))) (string->list (number->string x))))

(define (problem30)
  (displayln
   (apply +
          (filter
           (lambda (x) (= (apply +
                                 (map
                                  (lambda (x) (* x x x x x)) (number->digits x)))
                          x)) (range 10 500001)))))
(problem30)