Simplify path

class Solution:
    def simplifyPath(self, path: str) -> str:
        stack = []
        running_string = ""

        for c in path + "/":
            if c == "/":
                if running_string == ".." and len(stack) > 0:
                    stack.pop()
                if running_string not in [".", "", ".."]:
                    stack.append(running_string)
                running_string = ""
            else:
                running_string += c

        return "/" + "/".join(stack)

class Solution:
    def simplifyPath(self, path: str) -> str:
        stack = []

        for part in path.split("/"):
            if part == "..":
                if stack:
                    stack.pop()
            elif part not in [".", ""]:
                stack.append(part)

        return "/" + "/".join(stack)