[Swift]LeetCode1160. 拼写单词 | Find Words That Can Be Formed by Characters

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You are given an array of strings words and a string chars.

A string is good if it can be formed by characters from chars (each character can only be used once).

Return the sum of lengths of all good strings in words.

Example 1:

Input: words = ["cat","bt","hat","tree"], chars = "atach"
Output: 6
Explanation: 
The strings that can be formed are "cat" and "hat" so the answer is 3 + 3 = 6.

Example 2:

Input: words = ["hello","world","leetcode"], chars = "welldonehoneyr"
Output: 10
Explanation: 
The strings that can be formed are "hello" and "world" so the answer is 5 + 5 = 10.

Note:

1. 1 <= words.length <= 1000
2. 1 <= words[i].length, chars.length <= 100
3. All strings contain lowercase English letters only.

---

给你一份『词汇表』（字符串数组） words 和一张『字母表』（字符串） chars。

假如你可以用 chars 中的『字母』（字符）拼写出 words 中的某个『单词』（字符串），那么我们就认为你掌握了这个单词。

注意：每次拼写时，chars 中的每个字母都只能用一次。

返回词汇表 words 中你掌握的所有单词的 长度之和。

示例 1：

输入：words = ["cat","bt","hat","tree"], chars = "atach"
输出：6
解释： 
可以形成字符串 "cat" 和 "hat"，所以答案是 3 + 3 = 6。

示例 2：

输入：words = ["hello","world","leetcode"], chars = "welldonehoneyr"
输出：10
解释：
可以形成字符串 "hello" 和 "world"，所以答案是 5 + 5 = 10。

提示：

1. 1 <= words.length <= 1000
2. 1 <= words[i].length, chars.length <= 100
3. 所有字符串中都仅包含小写英文字母

---

216ms

class Solution {
  func countCharacters(_ words: [String], _ chars: String) -> Int {
    var res = 0
    var charMap = [Character: Int]()
    for char in chars {
      charMap[char] = charMap[char, default: 0] + 1
    }
    for word in words {
      var shouldAdd = true
      var charMapCopy = charMap
      for char in word {
        if let val = charMapCopy[char] {
          if val > 0 {
            charMapCopy[char] = val - 1
          } else {
            shouldAdd = false
            break
          }
        } else {
          shouldAdd = false
          break
        }
      }
      if shouldAdd {
        res += word.count
      }
    }
    return res
  }
}

---

244ms

class Solution {
    typealias Counter = [Character:Int]
    var charsCounter: Counter = Counter()
    var charsCount = 0
    func countCharacters(_ words: [String], _ chars: String) -> Int {
        var ans = 0
        charsCounter = getWordCounter(chars)
        charsCount = chars.count
        for word in words {
            if valid(word) {
                print(word)
                ans += word.count
            }
        }
        return ans
    }
    
    private func getWordCounter(_ word: String) -> Counter {
        var ans = Counter()
        for ch in word {
            if ans[ch] == nil {
                ans[ch] = 1
            } else {
                ans[ch] = ans[ch]! + 1
            }
        }
        return ans
    }
    private func valid(_ word: String) -> Bool {
        if word.count > charsCount {
            return false
        }
        var tempCharsCounter  =  charsCounter
        for key in word {
            if  tempCharsCounter[key]  == nil {
                return  false
            }
            tempCharsCounter[key] = tempCharsCounter[key]!  - 1
            if tempCharsCounter[key] == 0 {
                tempCharsCounter.removeValue(forKey: key)
            }
        }
        return true
    }
}

---

288ms

class Solution {
    func countCharacters(_ words: [String], _ chars: String) -> Int {
        
        if words.count == 0 { return 0 }
        if chars.count == 0 { return 0 }
        
        var charDict = [Character: Int]()
        var charStr = Array(chars)
        
        for ch in charStr {
            charDict[ch, default: 0] += 1
        }
        
        var result = 0
        for word in words {
            let wordChars = Array(word)
            var wordDict = charDict
            var canForm = true
            
            for wch in wordChars {
               guard var charFreq = wordDict[wch] else {
                   canForm = false
                   break 
               }
                charFreq -= 1
                
                if charFreq < 0 {
                    canForm = false
                    break
                }
                
                wordDict[wch] = charFreq
            }
            
            if canForm {
                result += word.count
            }
        }
        
        return result
    }
}

---

292ms

class Solution {
    func countCharacters(_ words: [String], _ chars: String) -> Int {
                
        let chars1 = Array(chars)
        var dic = [Character: Int]()
        for c in chars1 {
            dic[c, default: 0] += 1
        }

        var ans = 0
        for word in words {
            var tmpDic = dic
            let chs = Array(word)
            ans += chs.count
            for c in chs {
                if tmpDic[c ,default: 0] <= 0 {
                    ans -= chs.count
                    break
                }
                tmpDic[c ,default: 0] -= 1
            }
        }
        return ans
    }
}

---

520ms

class Solution {
    func countCharacters(_ words: [String], _ chars: String) -> Int {
        
        var count = 0
        
        let mappedChars = chars.reduce(into: [:]) {

            counts, character in
            counts[character, default: 0] += 1
            
        }
        
        for word in words {
            
            if isInChars(word, chars: mappedChars) {
                count += word.count
            }
            
        }
        
        return count
    }
    
    func isInChars(_ word: String, chars: [String.Element: Int]) -> Bool {
        
        let mappedWord = word.reduce(into: [:]) {
            counts, character in
            counts[character, default: 0] += 1
        }
        
        for each in mappedWord {
            
            if !chars.keys.contains(each.key) {
                return false
            }
            
            if each.value > chars[each.key]! {
                return false
            }
            
        }
        
        return true
    }
}

---

Runtime: 920 ms

Memory Usage: 21 MB

class Solution {
    func countCharacters(_ words: [String], _ chars: String) -> Int {
        var A:[Int:Int] = [Int:Int]()
        let arrChars:[Int] = Array(chars).map{$0.ascii}
        for c in arrChars
        {
            A[c - 97,default:0] += 1          
        }
        var ret:Int = 0
        for s in words
        {
            var cnt:[Int:Int] = [Int:Int]()
            let arrS:[Int] = Array(s).map{$0.ascii}
            for c in arrS
            {
                cnt[c - 97,default:0] += 1   
            }
            var found:Bool = false
            for k in 0..<26
            {
                if cnt[k,default:0] > A[k,default:0]
                {
                    found = true
                }
            }
            if !found
            {
                ret += s.count
            }
        }
        return ret        
    }
}

//Character扩展 
extension Character  
{  
  //Character转ASCII整数值(定义小写为整数值)
   var ascii: Int {
       get {
           return Int(self.unicodeScalars.first?.value ?? 0)
       }       
    }
}