task3 - add baseline

Author: proton

week4/priority-queues/task3/solution.rb

@@ -0,0 +1,29 @@
+### Taxicab numbers
+
+# A `taxicab` number is an integer that can be expressed as the sum of two cubes of positive integers in two different ways: `a^3 + b^3 = c^3 + d^3`.
+# For example, `1729` is the smallest taxicab number: `9^3 + 10^3 = 1^3 + 12^3`.
+# Design an algorithm to find all taxicab numbers with `a`, `b`, `c`, and `d` less than `n`.
+
+# - Version 1: Use time proportional to `(n^2)*log(n)` and space proportional to `n^2`.
+# - Version 2: Use time proportional to `(n^2)*log(n)` and space proportional to `n`.
+
+def baseline(n)
+  arr = []
+
+  1.upto(n) do |a|
+  1.upto(n) do |b|
+  1.upto(n) do |c|
+  1.upto(n) do |d|
+    next if [a, b, c, d].uniq.size < 4
+    r1 = a**3 + b**3
+    r2 = c**3 + d**3
+    arr << r1 if r1 == r2
+  end
+  end
+  end
+  end
+
+  arr.sort.uniq
+end
+
+p baseline(30)