15

ruby/15-3Sum.rb

@@ -0,0 +1,23 @@
+def three_sum(nums)
+ sums = []
+ nums.sort! # This is to get rid of duplicate solutions
+ nums.each_with_index do |num, idx|
+ next if idx.positive? && num == nums[idx - 1]
+
+ left = idx + 1
+ right = nums.length - 1
+ while left < right
+ case num + nums[left] + nums[right] <=> 0
+ when 1
+ right -= 1
+ when 0
+ sums << [num, nums[left], nums[right]]
+ left += 1
+ left += 1 while nums[left] == nums[left - 1] && left < right
+ when -1
+ left += 1
+ end
+ end
+ end
+ sums
+end