Implement Stack Using Arrays

Implement Stack Using Arrays

Implement a stack data structure using a fixed-size array.

Input format

The first line contains Q — the number of operations. Each of the next Q lines is one of: push x, pop, top, size.

Output format

For each pop print the removed value, for each top print the top value, for each size print the element count — one result per line. pop/top on an empty stack print -1.

Constraints

• Values fit in a 64-bit signed integer
• Trailing whitespace and a trailing newline are ignored by the judge

Read from stdin, write to stdout. Sample cases below show the exact format.

9
push 61
size
push 57
pop
pop
pop
size
pop
size

1
57
61
-1
0
-1
0

8
push 8
top
push 40
push 83
top
pop
push 5
size

8
83
83
3