add output for max_sub_array algorithm

Author: vbrazo

data_structures/arrays/maximum_subarray.rb

@@ -1,56 +1,66 @@
-#Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
-#A subarray is a contiguous part of an array.
+# Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.
+# A subarray is a contiguous part of an array.
 
-#Example 1:
-#Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
-#Output: 6
-#Explanation: [4,-1,2,1] has the largest sum = 6.
+# Example 1:
+# Input: nums = [-2,1,-3,4,-1,2,1,-5,4]
+# Output: 6
+# Explanation: [4,-1,2,1] has the largest sum = 6.
 
-#Example 2:
-#Input: nums = [1]
-#Output: 1
+# Example 2:
+# Input: nums = [1]
+# Output: 1
 
-#Example 3:
-#Input: nums = [5,4,-1,7,8]
-#Output: 23
+# Example 3:
+# Input: nums = [5,4,-1,7,8]
+# Output: 23
 
-#Constraints:
-#1 <= nums.length <= 3 * 104
-#-105 <= nums[i] <= 105
+# Constraints:
+# 1 <= nums.length <= 3 * 104
+# -105 <= nums[i] <= 105
 
+# Dynamic Programming Approach (Kadane's Algorithm) - O(n) Time / O(1) Space
+#
+# Init max_sum as first element
+# Return first element if the array length is 1
+# Init current_sum as 0
+# Iterate through the array:
+# if current_sum < 0, then reset it to 0 (to eliminate any negative prefixes)
+# current_sum += num
+# max_sum = current_sum if current_sum is greater than max_sum
+# Return max_sum
 
+# @param {Integer[]} nums
+# @return {Integer}
+def max_sub_array(nums)
+  # initialize max sum to first number
+  max_sum = nums[0]
 
+  # return first number if array length is 1
+  return max_sum if nums.length == 1
 
-#Dynamic Programming Approach (Kadane's Algorithm) - O(n) Time / O(1) Space
-#Init max_sum as first element
-#Return first element if the array length is 1
-#Init current_sum as 0
-#Iterate through the array:
-#if current_sum < 0, then reset it to 0 (to eliminate any negative prefixes)
-#current_sum += num
-#max_sum = current_sum if current_sum is greater than max_sum
-#Return max_sum   
+  # init current sum to 0
+  current_sum = 0
 
+  # iterate through array, reset current_sum to 0 if it ever goes below 0, track max_sum with highest current_sum
+  nums.each do |num|
+    current_sum = 0 if current_sum < 0
 
-# @param {Integer[]} nums
-# @return {Integer}
-def max_sub_array(nums)
-    #initialize max sum to first number
-    max_sum = nums[0]
-    
-    #return first number if array length is 1 
-    return max_sum if nums.length == 1
-    
-    #init current sum to 0
-    current_sum = 0
-    
-    #iterate through array, reset current_sum to 0 if it ever goes below 0, track max_sum with highest current_sum
-    nums.each do |num|
-      current_sum = 0 if current_sum < 0
-      current_sum += num
-      max_sum = [max_sum, current_sum].max
-    end
-    
-    #return answer
-    max_sum
+    current_sum += num
+
+    max_sum = [max_sum, current_sum].max
+  end
+
+  max_sum
 end
+
+nums = [-2, 1, -3, 4, -1, 2, 1, -5, 4]
+print max_sub_array(nums)
+# Output: 6
+
+nums = [1]
+print max_sub_array(nums)
+# Output: 1
+
+nums = [5, 4, -1, 7, 8]
+print max_sub_array(nums)
+# Output: 23