用clojure解决 euler problem 4

问题描述：

A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 

9009 = 91 99.

Find the largest palindrome made from the product of two 3-digit numbers.

解决方案：

(ns euler-problem-4.core  (:use clojure.contrib.math))(defn palindromic-number?  [number]  (loop      [number-string (str number)]    (if (or (empty? number-string) (= (count number-string) 1))      true      (if(= (first number-string) (last number-string))        (recur (drop-last (rest number-string)))        false))))(defn largest-palindromic-3-digit  []  (loop      [a 100, b 100, lpn 1]    (if (and (= 999 a) (= 999 b))     (if (palindromic-number? (* a b))          (max (* a b) lpn)           lpn)          (if (= a 999)        (if (palindromic-number? (* a b))          (recur 100 (inc b) (max (* a b) lpn))          (recur 100 (inc b) lpn))        (if (palindromic-number? (* a b))          (recur (inc a) b (max (* a b) lpn))          (recur (inc a) b lpn))))))(largest-palindromic-3-digit)

答案：906609