[Swift]LeetCode520. 检测大写字母 | Detect Capital

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Given a word, you need to judge whether the usage of capitals in it is right or not.

We define the usage of capitals in a word to be right when one of the following cases holds:

1. All letters in this word are capitals, like "USA".
2. All letters in this word are not capitals, like "leetcode".
3. Only the first letter in this word is capital if it has more than one letter, like "Google".

Otherwise, we define that this word doesn't use capitals in a right way.

 Example 1:

Input: "USA"
Output: True

 Example 2:

Input: "FlaG"
Output: False

 Note: The input will be a non-empty word consisting of uppercase and lowercase latin letters.

---

给定一个单词，你需要判断单词的大写使用是否正确。

我们定义，在以下情况时，单词的大写用法是正确的：

1. 全部字母都是大写，比如"USA"。
2. 单词中所有字母都不是大写，比如"leetcode"。
3. 如果单词不只含有一个字母，只有首字母大写， 比如 "Google"。

否则，我们定义这个单词没有正确使用大写字母。

示例 1:

输入: "USA"
输出: True

示例 2:

输入: "FlaG"
输出: False

注意: 输入是由大写和小写拉丁字母组成的非空单词。

---

 12ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        if word == nil || word == "" {return false}
        //大写
        let up:String = word.uppercased()
        //小写
        let low:String = word.lowercased()
        //首字母大写
        let str = word.capitalized
        if word == up || word == low || word == str
        {
            return true
        }
        return false
    }
}

---

8ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        if (word.count <= 1) {
            return true
        }
        
        var index = word.startIndex
        let end = word.index(before: word.endIndex)
        
        if (word[index] > "Z") {
            while (index < end) {
                word.formIndex(after: &index)
                if (word[index] < "a") {
                    return false
                }
            }
        } else {
            word.formIndex(after: &index)
            if (word[index] > "Z") {
                while (index < end) {
                    word.formIndex(after: &index)
                    if (word[index] < "a") {
                        return false
                    }
                }
            } else {
                while (index < end) {
                    word.formIndex(after: &index)
                    if (word[index] > "Z") {
                        return false
                    }
                }
            }
        }
        
        return true
    }
}

---

16ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        return word.isProper()
    }
}

extension Character {
    func isUppercased() -> Bool {
        let stringVal = String(self)
        return stringVal.uppercased() == stringVal
    }
}

extension String {
    func isProper() -> Bool {
        guard let first = self.first else { return false }
        let remaining = self.dropFirst()
        let remainingIsLower = remaining.lowercased() == remaining
        let remainingIsUpper = remaining.uppercased() == remaining
        return first.isUppercased() ? remainingIsUpper || remainingIsLower : remainingIsLower
    }
}

---

20ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        var allCaps = true
        var allNotCaps = true
        var firstCaps = true
        
        for i in 0..<word.count {
            let char = String(word[word.index(word.startIndex, offsetBy: i)])
            allCaps = allCaps && char == char.capitalized
            allNotCaps = allNotCaps && char != char.capitalized
            firstCaps = firstCaps && (i == 0 && char == char.capitalized) || firstCaps && (i != 0 && char != char.capitalized) 
        }
        
        return allCaps || allNotCaps || firstCaps
    }
}

---

20ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        let words = word.split(separator: " ")
        for word in words {
            var firstCapital = false
            var secondCapital = false
            for (index, scalar) in word.unicodeScalars.enumerated() {
                let value = scalar.value
                if index == 0 {
                    if value >= 65 && value <= 90 {
                        firstCapital = true
                    }
                } else if index == 1 {
                    if value >= 65 && value <= 90 {
                        if !firstCapital {
                            return false
                        }

                        secondCapital = true
                    }
                } else {
                    if value >= 65 && value <= 90 {
                        if !secondCapital {
                            return false
                        }
                    } else {
                        if secondCapital {
                            return false
                        }
                    }
                }
            }
        }

        return true
    }
}

---

24ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        let lower = word.lowercased()
        let upper = word.uppercased()
        let initials = upper[word.startIndex]
        let camel = lower.replacingCharacters(in: lower.startIndex..<lower.index(after: lower.startIndex), with: String(initials))
        
        
        return word == lower ||
        word == upper ||
        word == camel
    }
}

---

28ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        var i = 0
        var first = 0
        var flag = false
        var temp = true
        if word.count == 1 {
            return true
        }
        
        for w in word.unicodeScalars {
            
            var num = 0
            
            if i == 0 {
                first = Int(w.value)
            }else{
                num = Int(w.value)
            }
            
            if first >= 97 && first <= 122 {
                if num >= 97 && num <= 122 {
                    flag = true
                }else if num >= 65 && num <= 90 {
                    return false
                }
            }else{
                
                if num >= 97 && num <= 122 {
                    flag = true
                }else if num >= 65 && num <= 90 {
                    temp = false
                }
            }
            
            i += 1
        }
        
        if flag == false && temp == false {
            return true
        }
        
        return flag&&temp
    }
}

---

36ms

class Solution {
    func detectCapitalUse(_ word: String) -> Bool {
        return word == word.capitalized || word == word.uppercased() || word == word.lowercased()
        
    }
}