[Swift]LeetCode49. 字母异位词分组 | Group Anagrams

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Given an array of strings, group anagrams together.

Example:

Input: ["eat", "tea", "tan", "ate", "nat", "bat"],
Output:
[
  ["ate","eat","tea"],
  ["nat","tan"],
  ["bat"]
]

Note:

• All inputs will be in lowercase.
• The order of your output does not matter.

---

给定一个字符串数组，将字母异位词组合在一起。字母异位词指字母相同，但排列不同的字符串。

示例:

输入: ["eat", "tea", "tan", "ate", "nat", "bat"],
输出:
[
  ["ate","eat","tea"],
  ["nat","tan"],
  ["bat"]
]

说明：

• 所有输入均为小写字母。
• 不考虑答案输出的顺序。

---

68ms

class Solution {
    func hashValue(_ str: String) -> UInt64 {
        var hash: UInt64 = 0
        for code in str.unicodeScalars {
            let value = code.value - 97
            hash += UInt64(pow(5.0, Double(value)))
        }

        return hash
    }

    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var dic = [UInt64 : [String]]()
        for str in strs {
            let hash = hashValue(str)
            if let strings = dic[hash] {
                dic[hash] = strings + [str]
            } else {
                dic[hash] = [str]
            }
        }
        return Array(dic.values)
    }
}

---

124ms

class Solution {
    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var result = [String : [String]]()
        for item in strs {
            let newStr = reformateString(item)
            if let tempArray = result[newStr] {
                var newArray = tempArray
                newArray.append(item)
                result[newStr] = newArray
            } else {
                result[newStr] = [item]
            }
        }
        return [[String]](result.values)
    }
    
    func reformateString(_ str: String) -> String {
       return String([Character](str).sorted(by: <))
    }
}

---

132ms

class Solution {
    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var res = [[String]]()
        var dict = [String: [String]]()
        strs.forEach{(string) in
            let charArray = Array(string).sorted(){$0 < $1}
            let key = String(charArray)
            if dict[key] != nil {
                dict[key]?.append(string)
            }else {
                dict[key] = [string]
            }
        }
        for key in dict.keys {
            res.append(dict[key]!)
        }
        return res
    }
}

---

140ms

class Solution {
    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var map = [String: [String]]()
        
        for str in strs {
            let key = String(str.sorted())
            map[key, default: []].append(str)
        }
        
        return Array(map.values)
    }
}

---

148ms

class Solution {
    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var map: [String: [String]] = [:]
        for str in strs {
            let chars = str.sorted()
            let key = String(chars)
            if var list = map[key] {
                list.append(str)
                map[key] = list
            } else {
                map[key] = [str]
            }
        }
        return Array(map.values)
    }
}

---

316ms

class Solution {
    func groupAnagrams(_ strs: [String]) -> [[String]] {
        var groups = [String: [String]]()
        for str in strs {
            let strSorted = String(str.sorted())
            if groups[strSorted] == nil {
                groups[strSorted] = [str]
            } else {
                groups[strSorted]?.append(str)
            }
        }
        return groups.map { $1 }
    }
}