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 Summary

Constructors

Constructor and Description
CustomStack(int maxSize)

Method Summary

Modifier and Type	Method and Description
void	increment(int k, int val)
int	pop()
void	push(int x)

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

CustomStack

public CustomStack(int maxSize)

Method Detail

push

public void push(int x)

pop

public int pop()

increment

public void increment(int k,
                      int val)