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AsteriodCollision.java
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65 lines (55 loc) · 1.78 KB
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package Leetcode;
import java.util.Arrays;
import java.util.Stack;
public class AsteriodCollision
{
public static void main( String[] args )
{
char[][] A = new char[][]{ { '0', '1' } };
AsteriodCollision asteroidCollision = new AsteriodCollision();
System.out.println( Arrays.toString( asteroidCollision.asteroidCollision( new int[]{ -2, -1, 1, 2 } ) ) );
}
public int[] asteroidCollision( int[] asteroids )
{
if( asteroids == null || asteroids.length == 0 )
return new int[]{};
Stack<Integer> stack = new Stack<>();
for( int i = 0; i < asteroids.length; i++ )
{
if( stack.isEmpty() || asteroids[i] > 0 )
stack.push( asteroids[i] );
else
{
while( true )
{
int peek = stack.peek();
if( peek < 0 )
{
stack.push( asteroids[i] );
break;
}
else if( peek > -asteroids[i] )
break;
else if( peek == -asteroids[i] )
{
stack.pop();
break;
}
else if( peek < -asteroids[i] )
{
stack.pop();
if( stack.isEmpty() )
{
stack.push( asteroids[i] );
break;
}
}
}
}
}
int[] result = new int[ stack.size() ];
for( int i = stack.size() - 1; i >= 0; i-- )
result[i] = stack.pop();
return result;
}
}