Adding Solution for 3663

Ruby/3663.rb

@@ -0,0 +1,40 @@
+# 268. Missing Number
+
+# @param {Integer} n
+# @return {Integer}
+def get_least_frequent_digit(n)
+  l = Array.new(10, 0)
+  while n != 0 do
+    n, d = n.divmod(10)
+    l[d] += 1
+  end
+
+  min_value = 9999999
+  min_index = 0
+  i = 0
+  while i < 10 do
+    if l[i] > 0 and l[i] < min_value then
+      min_value = l[i]
+      min_index = i
+    end
+    i += 1
+  end
+
+  return min_index
+end
+
+def main()
+  def r(n, exp)
+    puts "get_least_frequent_digit(#{n}) = #{get_least_frequent_digit(n)} | exp: #{exp}"
+  end
+
+  r(1553322, 1)
+  r(723344511, 2)
+  r(10, 0)
+
+end
+
+
+if __FILE__ == $0
+  main()
+end