394-DecodeString

Decode String

Problem can be found in here!

Solution: Stack

def decodeString(self, s):
    stack = []
    current_number = 0
    current_string = ""
    for char in s:
        if char == "[":
            stack.append(current_string)
            stack.append(current_number)
            current_number, current_string = 0, ""
        elif char == "]":
            num = stack.pop()
            prevString = stack.pop()
            current_string = prevString + num*current_string
        elif char.isdigit():
            current_number = current_number*10 + int(char)
        else:
            current_string += char
            
    return current_string

Time Complexity: , Space Complexity: