Project Euler problem 19 solution

euler19.clj

(defn p19-solution []
  (let [multiple? #(zero? (rem %1 %2))
        leap-year? #(or (and (multiple? % 4)
                             (not (multiple? % 100)))
                        (multiple? % 400))
        february #(if (leap-year? %) 29 28)
        mdays [31 28 31 30 31 30 31 31 30 31 30 31]
        mdays (map #(constantly %) mdays)
        mdays (apply juxt (assoc (vec mdays) 1 february))
        months (mapcat mdays (range 1901 2001))
        days1900 (reduce + (mdays 1900))
        sunday? #(= 6 (rem % 7))]
    (first
     (reduce (fn [[n d] m]
               [(if (sunday? d) (inc n) n) (+ d m)])
             [0 days1900]
             months))))