dialect.clj

;;problem 3 largest prime factor of 600851475143

(defn prime? [x]
  (if (>= x 2) (zero? (count (filter #(divides? x %) (range 2 (inc (int (sqrt x))))))) false))

(defn get-biggest-prime-factor [x]
  (if (prime? x)
    x
    (/ x (first
          (filter #(prime? (/ x %))
                  (filter #(divides? x %)
                          (range 2 (inc (int (sqrt x))))))))))

(get-biggest-prime-factor 600851475143)