0594

0501-0600/0594_longest_harmonious_subsequence.rb

@@ -0,0 +1,29 @@
+# @param {Integer[]} nums
+# @return {Integer}
+def find_lhs(nums) # sort + sliding window
+ nums.sort!
+
+ # since the nums is sorted, 
+ # now we only need to maintain the window that has max-min=1 and count
+ max = 0
+ i = j = 0
+ while j < nums.size
+ max = [max, j-i+1].max if nums[j] - nums[i] == 1
+ i += 1 while i < j && nums[j] - nums[i] > 1
+ j += 1
+ end
+
+ max
+end
+
+# hash-table
+def find_lhs(nums)
+ counter = nums.tally
+ max = 0
+ counter.each { |num, count|
+ # subsequence of {num} and subsequence of {num + 1} will form a harmonious subsequence
+ max = [max, counter[num+1] + count].max if counter.has_key?(num + 1)
+ }
+
+ max
+end