595.Check Whether a Stack Is Empty After Each Operation
Easy
Process
ops on an initially empty stack: a positive number means push it, and 0 means pop (ignored if the stack is empty). After every operation, record 1 if the stack is empty and 0 if it is not.
isEmptyisEmptyA stack operation that answers whether the stack currently holds no items. is the guard behind every safe pop and peek. This problem also shows a useful habit: notice which information a question really needs. Emptiness depends only on how many items are on the stack, so a single counter can replace the stack itself.
Example 1:
Input: ops = [7,0,0,3,8,0]
Output: [0,1,1,0,0,0]
Example 2:
Input: ops = [0,0]
Output: [1,1]
+ 3 hidden test cases run on Submit.
Constraints:
- ●
1 ≤ ops.length ≤ 1000 - ●
0 ≤ ops[i] ≤ 1000000 (a positive value means push it, 0 means pop)
ops =
[7, 0, 0, 3, 8, 0]