text: """394. Decode String"""
  
  class Solution(object):
      def decodeString(self, s):
          """
          :type s: str
          :rtype: str
          """
          ### Practice:
          curstring = ''
          curnum = 0
          stack = []
          for i in s:
              if i == '[':
                  stack.append(curstring)
                  stack.append(curnum)
                  curstring = ''
                  curnum = 0
              elif i.isdigit():
                  curnum = 10*curnum + int(i)
              elif i == ']':
                  prevnum = stack.pop()
                  prevstring = stack.pop()
                  curstring = prevstring + prevnum*curstring
              else:
                  curstring += i
  
          return curstring
  
  
  
  
          ##### Practice:
          curnum = 0
          curstring = ''
          stack = []
          for i in s:
              if i == '[':
                  stack.append(curstring)
                  stack.append(curnum)
                  curstring = ''
                  curnum = 0
              elif i.isdigit():
                  curnum = curnum*10 + int(i)
              elif i == ']':
                  prevnum = stack.pop()
                  prevstring = stack.pop()
                  curstring = prevstring + prevnum*curstring
              else:
                  curstring += i
  
          return curstring
  
  
          ############
          curstring = ""
          curnum = 0
          stack = []
  
          for i in s:
              if i == "[":
                  stack.append(curstring)
                  stack.append(curnum)
                  curstring = ""
                  curnum = 0
  
              elif i.isdigit():
                  curnum = curnum*10 + int(i)
  
              elif i == "]":
                  num = stack.pop() # num is not curnum
                  prevstring = stack.pop()
                  curstring = prevstring + num*curstring
  
              else:
                  curstring += i
  
          return curstring
  