SDE Path

Asteroid Collision

Medium

Asteroid Collision

Simulate collisions of asteroids represented as an array of integers, using a stack.

Input format

The first line contains N. The second line contains N non-zero integers — positive moves right, negative moves left; absolute value is size. When two collide the smaller explodes (both explode if equal).

Output format

Print the surviving asteroids in order, space-separated (or -1 if none survive).

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.

Sample cases

Example 1
Input
3
5 10 -5
Expected output
5 10
Example 2
Input
2
8 -8
Expected output
-1