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Minimum Size Subarray Sum

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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.

A subarray is a contiguous non-empty sequence of elements within an array.

Examples

Example 1
Input
target = 7, nums = [2,3,1,2,4,3]
Output
2

The subarray [4,3] has sum 7 which is >= target, and its length 2 is the smallest possible.

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

The single element [4] already meets the target of 4.

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

The total sum of the array is 8 which is less than 11, so no valid subarray exists.

Constraints

  • 1 <= target <= 109
  • 1 <= nums.length <= 105
  • 1 <= nums[i] <= 104

Optimal complexity

Time

O(n)

Space

O(1)

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