ypsilon-takai

;; Problem 62  : 2011/11/17
;; "Elapsed time: 2139.92309 msecs"

(defn pe62 [tgt-count]
  (loop [num 9
	 res-map {}]
    (let [cubed (* num num num)
	  num-key (sort (num-to-list cubed))]
      (if (= (dec tgt-count) (count (res-map num-key)))
	(cons num (res-map num-key))

ypsilon-takai

;; Problem 63  : 2011/11/17
;; "Elapsed time: 1.326705 msecs"

(require '[clojure.contrib.math :as math])

(defn digits-of-pow [x n]
  (count (str (math/expt x n))))

(defn pe63 []
  (for [x (range 1 10)]

ypsilon-takai

;; Problem 64  : 2011/11/25
;; "Elapsed time: 755.433163 msecs"

;; (sqrt X)+M
;; -----------
;;      N

(defn int-floor [n]
  (Math/round (Math/floor n)))

ypsilon-takai

;; Problem 65  : 2011/11/25
;; "Elapsed time: 3.193423 msecs"

(defn cf-seq-of-e [n]
  (cond (zero? n) 2
	(= (rem n 3) 2) (* 2 (/ (inc n) 3))
	:else 1))

(defn-memo cf-numerator [n a-seq]
  (cond (zero? n) 1

ypsilon-takai

;; reviced for clojure 1.4

;; Problem 67  : 2011/11/28
;; "Elapsed time: 52.128413 msecs"

 (defn pe-67 [input-list]
  (apply max
	 (reduce (fn [root new]
		   (let [rt-r (cons 0 root)
			 rt-l (conj root 0)]

ypsilon-takai

;; Problem 66  : 2011/11/29
;; "Elapsed time: 67.348225 msecs"

;; treat all num as
;; (sqrt X)+M
;; -----------
;;      N

(defn int-floor [x]
  (Math/round (Math/floor x)))

ypsilon-takai

;; Problem 68  : 2011/12/1
;;"Elapsed time: 89.450754 msecs"

(defn check-pe68 [tgt]
  (let [[[a2 a3 a4 a5] [b1 b2 b3 b4 b5]] tgt]
    (if (= 14
	   (+ 6 b1 b2) (+ a2 b2 b3) (+ a3 b3 b4)
	   (+ a4 b4 b5) (+ a5 b5 b1))
      [6 b1 b2 a2 b2 b3 a3 b3 b4 a4 b4 b5 a5 b5 b1]
      false)))

ypsilon-takai

;; Problem 69  : 2011/12/6

;; This needs too long time.
;; "Elapsed time: 980693.545995 msecs"

(defn get-n-slash-phi-n [n]
  (/ 1 (reduce * (map #(- 1 (/ 1 %)) (distinct (factors n))))))

(defn pe-69 [end-val]
  (reduce #(if (> (first %1) (first %2)) %1 %2)

ypsilon-takai

;; Problem 70  : 2011/12/8
;; "Elapsed time: 19858.886534 msecs"

(defn permutation-num? [n m]
  (= (sort (seq (str n)))
     (sort (seq (str m)))))

(defn pe-70 [limit]
  (reduce #(if (< (first %1) (first %2)) %1 %2)
	  (filter #(permutation-num? (second %) (last %))

ypsilon-takai

;; Problem 71  : 2011/12/8
;; "Elapsed time: 151.987474 msecs"

(defn my-numerator [n]
  (if (integer? n)
    n
    (numerator (rationalize n))))

(defn my-denominator [n]
  (if (integer? n)