Correct min stack (?)

leetcode/stuff.py

@@ -143,22 +143,18 @@ class Roman:
 class MinStack:
     def __init__(self):
         self._v: list[int] = []
-        self._min: int | None = None
+        self._min: list[int] = []
 
     def push(self, val: int) -> None:
         self._v.append(val)
-
-        if self._min is None or self._min > val:
-            self._min = val
+        self._min.append(min(val, self._min[-1] if self._min else val))
 
     def pop(self) -> None:
-        popped = self._v.pop(-1)
-
-        if popped == self._min:
-            self._min = min(self._v)
+        self._v.pop(-1)
+        self._min.pop(-1)
 
     def top(self) -> int:
         return self._v[-1]
 
     def getMin(self) -> int:  # no qa
-        return typing.cast(int, self._min)
+        return self._min[-1]