383. 赎金信

题目链接：https://leetcode-cn.com/problems/ransom-note/
执行用时：36 ms, 在所有 Swift 提交中击败了97.22%的用户
内存消耗：13.9 MB, 在所有 Swift 提交中击败了86.11%的用户

解题思路

和242一样的解法

class Solution {
    func canConstruct(_ ransomNote: String, _ magazine: String) -> Bool {
        if ransomNote.count > magazine.count {
            return false
        }
        var table = [Int].init(repeating: 0, count: 26)
        let chValue = Int("a".unicodeScalars.first!.value)
        for item in magazine.unicodeScalars {
            table[Int(item.value) - chValue] += 1
        }
        for i in ransomNote.unicodeScalars {
            table[Int(i.value) - chValue] -= 1
        }
        guard table.first(where: {$0 < 0}) != nil else{
            return true
        }
        return false
    }
}