Package g1301_1400.s1381_design_a_stack_with_increment_operation

Class CustomStack

java.lang.Object
g1301_1400.s1381_design_a_stack_with_increment_operation.CustomStack
public class CustomStack extends Object
1381 - Design a Stack With Increment Operation.

Medium

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],[],[],[],[]]

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.

  • Constructor Details

    • CustomStack

      public CustomStack(int maxSize)

  • Method Details

    • push

      public void push(int x)

    • pop

      public int pop()

    • increment

      public void increment(int k, int val)