383.Ransom Note

Given an arbitrary ransom note string and another string containing letters from all the magazines, write a function that will return true if the ransom note can be constructed from the magazines ; otherwise, it will return false.

Each letter in the magazine string can only be used once in your ransom note.

Note:
You may assume that both strings contain only lowercase letters.

canConstruct("a", "b") -> false
canConstruct("aa", "ab") -> false
canConstruct("aa", "aab") -> true

Submissions

• golang

func canConstruct(ransomNote string, magazine string) bool {
    save := make(map[rune]int)
    for _,char := range magazine{
        if _, ok := save[char]; ok{
            save[char] += 1
        }else{
            save[char] = 1
        }
    }
    for _,char := range ransomNote{
        if _, ok := save[char]; ok && save[char] > 0{
            save[char] -= 1
        }else{
            return false
        }
    }
    return true
}

• scala

object Solution {
    def canConstruct(ransomNote: String, magazine: String): Boolean = {
      if (magazine.size < ransomNote.size) return false
      val Array(map1, map2) = Array(ransomNote, magazine).map(_.toCharArray.groupBy(identity).mapValues(_.size))
      if (!(map1.keySet subsetOf map2.keySet)) return false
      map2.transform((k, v) => v - map1.getOrElse(k, 0)).filter(_._2 < 0).size <= 0
    }
}