//

// MinimumSizeSubarrySum.swift

// ConquerAlgorithm

//

// Created by Freelf on 2021/2/20.

// Copyright © 2021 Freelf. All rights reserved.

//

// 209. 长度最小的子数组

// https://leetcode-cn.com/problems/minimum-size-subarray-sum/

import Foundation

class MinimumSizeSubarrySumSolution {

func minSubArrayLen(_ target: Int, _ nums: [Int]) -> Int {

var length = -1

for i in 0 ..< nums.count {

var sum = 0

for j in i ..< nums.count {

sum += nums[j]

if sum >= target {

let newLength = j - i + 1;

length = length == -1 ? newLength : min(newLength, length)

}

}

}

return length == -1 ? 0 : length

}

func minSubArrayLen2(_ target: Int, _ nums: [Int]) -> Int { // 滑动窗口

var length = -1

var sum = 0

var startIndex = 0

for i in 0 ..< nums.count {

sum += nums[i]

while sum >= target {

let newLength = i - startIndex + 1

length = length == -1 ? newLength : min(newLength, length)

sum -= nums[startIndex] // 窗口开始滑动

startIndex += 1

}

}

return length == -1 ? 0 : length

}

}