Design a Stack With Increment Operation

Medium · Stack & Monotonic Stack · about 15 minutes

Asked at Amazon, Google, Microsoft.

Design a stack with a maximum size.

• CustomStack(maxSize) creates it.
• push(x) pushes x if the stack has fewer than maxSize elements.
• pop() pops and returns the top, or -1 if empty.
• increment(k, val) adds val to the bottom k elements (all of them if fewer).