Initial data commit

Task/Ethiopian-multiplication/Clojure/ethiopian-multiplication.clj

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+(defn halve [n]
+  (bit-shift-right n 1))
+
+(defn twice [n]          ; 'double' is taken
+  (bit-shift-left n 1))
+
+(defn even [n]           ; 'even?' is the standard fn
+  (zero? (bit-and n 1)))
+
+(defn emult [x y]
+  (reduce +
+    (map second
+      (filter #(not (even (first %))) ; a.k.a. 'odd?'
+        (take-while #(pos? (first %))
+          (map vector
+            (iterate halve x)
+            (iterate twice y)))))))
+
+(defn emult2 [x y]
+  (loop [a x, b y, r 0]
+    (if (= a 1)
+      (+ r b)
+      (if (even a)
+        (recur (halve a) (twice b) r)
+        (recur (halve a) (twice b) (+ r b))))))