Minimum Size Subarray Sum
Created: September 8, 2019 by [lek-tin]
Last updated: September 8, 2019
Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn’t one, return 0 instead.
Example:
Input: s = 7, nums = [2,3,1,2,4,3]
Output: 2
Explanation: the subarray [4,3] has the minimal length under the problem constraint.
Follow up:
If you have figured out the O(n) solution, try coding another solution of which the time complexity is O(n log n).
# time: `O(n)`
class Solution:
def minSubArrayLen(self, target: int, nums: List[int]) -> int:
n = len(nums)
if n == 0:
return 0
left = 0
count = n+1
currSum = 0
for i in range(n):
currSum += nums[i]
while currSum >= target:
count = min(count, i - left + 1)
currSum -= nums[left]
left += 1
return 0 if count == n+1 else count