Swift——LeetCode 344 反转字符串

344. 反转字符串

双指针法

    func reverseString(_ s: inout [Character]) {
        if s.count == 0 {
            return
        }
        var x = 0
        var y = s.count - 1
        while(x < y){
            s.swapAt(x, y)
            x += 1
            y -= 1
        }
    }

递归

    func reverseString_methods2(_ s: inout [Character]) {
        if s.count == 0 {
          return
        }
        recursive_reverseString(&s, 0, s.count-1)
    }
    
    func recursive_reverseString(_ s: inout [Character], _ start:Int, _ end : Int) {
      if start >= end {
        return
      } else {
        s.swapAt(start, end)
        recursive_reverseString(&s,start+1,end-1)
      }
    }

自带函数

    func reverseString_methods3(_ s: inout [Character]) {
        if s.count == 0 {
            return
        }
        s = s.reversed()
    }