Source code for titan_pylib.data_structures.stack.stack

 1from typing import TypeVar, Generic, Iterable
 2
 3T = TypeVar("T")
 4
 5

[docs]
 6class Stack(Generic[T]):
 7
 8    # コンセプト：popをしないStack
 9
10    def __init__(self, a: Iterable[T] = []):
11        self.data: list[T] = list(a)
12        self.back: int = len(self.data)
13

[docs]
14    def pop(self) -> T:
15        assert self, f"IndexError: pop() from empty {self.__class__.__name__}."
16        self.back -= 1
17        return self.data[self.back]

18

[docs]
19    def append(self, val: T) -> None:
20        if self.back < len(self.data):
21            self.data[self.back] = val
22        else:
23            self.data.append(val)
24        self.back += 1

25

[docs]
26    def top(self) -> T:
27        return self.data[self.back - 1]

28
29    def __getitem__(self, k: int) -> T:
30        if k < 0:
31            k += self.back
32        return self.data[k]
33
34    def __iter__(self):
35        self.__iter = -1
36        return self
37
38    def __next__(self):
39        if self.__iter + 1 >= self.back:
40            raise StopIteration
41        self.__iter += 1
42        return self.data[self.__iter]
43
44    def __len__(self):
45        return self.back
46
47    def __bool__(self):
48        return self.back > 0
49
50    def __str__(self):
51        return "[" + ", ".join(map(str, self)) + "]"
52
53    def __repr__(self):
54        return f"{self.__class__.__name__}({self})"