m1381.py

"""Design a Stack With Increment Operation
Design a stack which supports the following operations.

Implement the CustomStack class:

* CustomStack(int maxSize) Initializes the object with maxSize which is the
  maximum number of elements in the stack or do nothing if the stack reached
  the maxSize.
* void push(int x) Adds x to the top of the stack if the stack hasn't reached
  the maxSize.
* int pop() Pops and returns the top of stack or -1 if the stack is empty.
* void inc(int k, int val) Increments the bottom k elements of the stack by
  val. If there are less than k 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],
      [],
      [],
      [],
      [],
  ]
  [
      null,
      null,
      null,
      2,
      null,
      null,
      null,
      null,
      null,
      103,
      202,
      201,
      -1,
  ]
* 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 of increment, push and pop
  each separately.
"""