0209-minimum-size-subarray-sum.rb

# frozen_string_literal: true

# 209. Minimum Size Subarray Sum
# https://leetcode.com/problems/minimum-size-subarray-sum
# Medium

=begin
Given an array of positive integers nums and a positive integer target, return the minimal length of a subarray whose sum is greater than or equal to target. If there is no such subarray, return 0 instead.

Example 1:
Input: target = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: The subarray [4,3] has the minimal length under the problem constraint.

Example 2:
Input: target = 4, nums = [1,4,4]
Output: 1

Example 3:
Input: target = 11, nums = [1,1,1,1,1,1,1,1]
Output: 0

Constraints:
1 <= target <= 109
1 <= nums.length <= 105
1 <= nums[i] <= 104
=end

# @param {Integer} target
# @param {Integer[]} nums
# @return {Integer}
defmin_sub_array_len(target,nums)
return0ifnums.empty?
min=nil
i,j=0,0
sum=nums[i]
whilej < nums.size
ifsum < target
j += 1
sum += nums[j]ifj < nums.size
next
end
ifi == j
return1
end
length=j - i + 1
min=lengthifmin.nil?
min=lengthifmin > length
i += 1
sum -= nums[i - 1]
end
min || 0
end

# ********************#
# TEST #
# ********************#

require"test/unit"
classTest_min_sub_array_len < Test::Unit::TestCase
deftest_
assert_equal2,min_sub_array_len(7,[2,3,1,2,4,3])
assert_equal1,min_sub_array_len(4,[1,4,4])
assert_equal0,min_sub_array_len(11,[1,1,1,1,1,1,1,1])
end
end