ARTS #17

Algorithm

本周选择的算法题是：Smallest Range I

规则如下：

Given an array A of integers, for each integer A[i] we may choose any x with -K <= x <= K, and add x to A[i].

After this process, we have some array B.

Return the smallest possible difference between the maximum value of B and the minimum value of B.

Example 1:

Input: A = [1], K = 0
Output: 0
Explanation: B = [1]

Example 2:

Input: A = [0,10], K = 2
Output: 6
Explanation: B = [2,8]

Example 3:

Input: A = [1,3,6], K = 3
Output: 0
Explanation: B = [3,3,3] or B = [4,4,4]

Note:

1 <= A.length <= 10000
0 <= A[i] <= 10000
0 <= K <= 10000

Solution

我实现的方案：

Runtime：132 ms，快过 86.95%。

Memory：14.8 MB，低于 11.11%。

class Solution:
    def smallestRangeI(self, A: List[int], K: int) -> int:
#         if not A:
#             return 0

#         minimum, maximum = A[0], A[0]
#         for i in range(1, len(A)):
#             minimum, maximum = min(minimum, A[i]), max(maximum, A[i])
        
#         return max(0, maximum - minimum - 2 * K)
        return max(0, max(A) - min(A) - 2 * K)

Review

Dark Mode on iOS 13

Backwards compatibility for iOS 13 system colors

两篇关于 iOS 13 适配的文章，Dark Mode 主要需要对色值进行管理。

前者花了些篇幅使用脚本找出需要调整的地方，如从 .swift 文件中找：

$ find . -name '*.swift'  \
    -exec sed -i '' -E 's/#colorLiteral\(red: (.*), green: (.*), blue: (.*), alpha: (.*)\)/UIColor(red: \1, green: \2, blue: \3, alpha: \4)/ {} \;

从 xib 或 storyboard 中找：

$ find . -name '*.xib' -or -name '*.storyboard' \
    -exec echo {} \;        \
    -exec xmlstarlet sel -t \
            -m "//color[@colorSpace='custom']" -c . -n  {} \;

Main.storyboard
<color red="1" green="0.69019607843137254" blue="0.0" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>

通过工具可以高效的找出需要修改的地方。

后面那篇主要是关于兼容性的，作者很巧妙的通过一个 ColorCompatibility 类来实现版本间的兼容：

enum ColorCompatibility {
    static var label: UIColor {
        if #available(iOS 13, *) {
            return .label
        }
        return UIColor(red: 1.0, green: 1.0, blue: 1.0, alpha: 1.0)
    }

    static var secondaryLabel: UIColor {
        if #available(iOS 13, *) {
            return .secondaryLabel
        }
        return UIColor(red: 0.9215686274509803, green: 0.9215686274509803, blue: 0.9607843137254902, alpha: 0.6)
    }

    // ... 21 more definitions: full code at the bottom of this post
}

通过给 iOS 13 以下的系统实现相似的功能，做到业务端最少的修改量，还能后向兼容。

Tip

通过 travis.ci 的 matrix 可以为同一个项目/工程执行不同的 build 计划：

matrix:
  include:
    - osx_image: xcode11
      xcode_sdk: iphonesimulator12.2
      env: DESTINATION="platform=iOS Simulator,name=iPhone 11"
    
    - osx_image: xcode11
      xcode_sdk: iphonesimulator13.0
      env: DESTINATION="platform=iOS Simulator,name=iPhone 11"

before_install:
  - rvm use system
  - brew install ruby
  - sudo gem install cocoapods -v '1.8.0'
  - pod repo update

script:
  - xcodebuild clean build test -workspace Example/DKImagePickerControllerDemo.xcworkspace -scheme DKImagePickerControllerDemo -destination "$DESTINATION"

env 可以用在为不同的 sdk、image 指定不同的环境变量

分享一篇关于坑位曝光实现方案：关于坑位曝的光检测方案

Algorithm

Solution

Review

Tip

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