简单的编程题，响应题目要求，不用额外的存储空间

public class Solution {
    public ArrayList<Integer> getRow(int rowIndex) {
        // Start typing your Java solution below
        // DO NOT write main() function
        ArrayList<Integer> result = new ArrayList<Integer>();
        if (rowIndex < 0)
            return result;
        for (int i=0; i<=rowIndex; i++) {
            result.add(1);
            for (int j=result.size()-2; j>=0; j--) {
                int value = result.get(j);
                if (j > 0)
                    value += result.get(j-1);
                result.set(j, value);
            }
        }
        return result;
    }
}