# Swift LeetCode SlideWindow

1 min readAug 4, 2021

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209. Minimum Size Subarray Sum

Given an array of positive integers `nums` and a positive integer `target`, return the minimal length of a contiguous subarray `[numsl, numsl+1, ..., numsr-1, numsr]` of which the 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: 2Explanation: 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] <= 105`

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))`.

Question

`class Solution { func minSubArrayLen(_ target: Int, _ nums: [Int]) -> Int { }}`

Solution

`func minSubArrayLen(_ target: Int, _ nums: [Int]) -> Int {   var windowSum = 0, windowStart = 0   var minWindowSize = Int.max   for windowEnd in 0..<nums.count{   windowSum += nums[windowEnd]   while (windowSum >= target) {     minWindowSize = min(minWindowSize, windowEnd - windowStart + 1)     windowSum -= nums[windowStart]     windowStart += 1   }  } return minWindowSize == Int.max ? 0 : minWindowSize}`

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Major in physical education. Football referee. And high interest in looking the world through the numbers.