June 2018 Update

Task/Hamming-numbers/Julia/hamming-numbers.julia

@@ -1,19 +1,19 @@
-n = 40
+function hamming(n::Integer)
+    seq   = collect(0:n)
+    pwrs2 = 2 .^ seq
+    pwrs3 = 3 .^ seq
+    pwrs5 = 5 .^ seq
 
-powers_2 = 2.^[0:n-1]
-powers_3 = 3.^[0:n-1]
-powers_5 = 5.^[0:n-1]
+    matrix = pwrs2 * pwrs3'
+    pwrs23 = sort(reshape(matrix, length(matrix)))
 
-matrix = powers_2 * powers_3'
-powers_23 = sort(reshape(matrix,length(matrix),1),1)
+    matrix = pwrs23 * pwrs5'
+    if any(x -> x < 0, matrix) warn("overflow values in result, try to use big($n) instead") end
+    return sort(reshape(matrix, length(matrix)))
+end
 
-matrix = powers_23 * powers_5'
-powers_235 = sort(reshape(matrix,length(matrix),1),1)
+x = hamming(big(100))
 
-#
-# Remove the integer overflow values.
-#
-powers_235 = powers_235[powers_235 .> 0]
-
-println(powers_235[1:20])
-println(powers_235[1691])
+println("First 20 hamming numbers: ", join(x[1:20], ", "))
+println("1691-th hamming number: ", x[1691])
+println("Million-th hamming number: ", x[1000000])