Design a stack which supports the following operations.
Implement the CustomStack
class:
-
CustomStack(int maxSize)
Initializes the object withmaxSize
which is the maximum number of elements in the stack or do nothing if the stack reached themaxSize
. -
void push(int x)
Addsx
to the top of the stack if the stack hasn't reached themaxSize
. -
int pop()
Pops and returns the top of stack or -1 if the stack is empty. -
void inc(int k, int val)
Increments the bottomk
elements of the stack byval
. If there are less thank
elements in the stack, just increment all the elements in the stack.
Example 1:
Input
["CustomStack","push","push","pop","push","push","push","increment","increment","pop","pop","pop","pop"]
[[3],[1],[2],[],[2],[3],[4],[5,100],[2,100],[],[],[],[]]
Output
[null,null,null,2,null,null,null,null,null,103,202,201,-1]
Explanation
CustomStack customStack = new CustomStack(3); // Stack is Empty []
customStack.push(1); // stack becomes [1]
customStack.push(2); // stack becomes [1, 2]
customStack.pop(); // return 2 --> Return top of the stack 2, stack becomes [1]
customStack.push(2); // stack becomes [1, 2]
customStack.push(3); // stack becomes [1, 2, 3]
customStack.push(4); // stack still [1, 2, 3], Don't add another elements as size is 4
customStack.increment(5, 100); // stack becomes [101, 102, 103]
customStack.increment(2, 100); // stack becomes [201, 202, 103]
customStack.pop(); // return 103 --> Return top of the stack 103, stack becomes [201, 202]
customStack.pop(); // return 202 --> Return top of the stack 102, stack becomes [201]
customStack.pop(); // return 201 --> Return top of the stack 101, stack becomes []
customStack.pop(); // return -1 --> Stack is empty return -1.
Constraints:
-
1 <= maxSize <= 1000
-
1 <= x <= 1000
-
1 <= k <= 1000
-
0 <= val <= 100
- At most
1000
calls will be made to each method ofincrement
,push
andpop
each separately.
SOLUTION:
class CustomStack:
def __init__(self, maxSize: int):
self.stack = []
self.maxSize = maxSize
def push(self, x: int) -> None:
if len(self.stack) < self.maxSize:
self.stack.append(x)
def pop(self) -> int:
if len(self.stack) > 0:
return self.stack.pop()
return -1
def increment(self, k: int, val: int) -> None:
i = 0
while i < k and i < len(self.stack):
self.stack[i] += val
i += 1
# Your CustomStack object will be instantiated and called as such:
# obj = CustomStack(maxSize)
# obj.push(x)
# param_2 = obj.pop()
# obj.increment(k,val)
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