[leetcode]Pascal's Triangle II

简单题。

public class Solution {

    public ArrayList<Integer> getRow(int rowIndex) {

        ArrayList<Integer> ans = new ArrayList<Integer>();

        ans.add(1);

        ArrayList<Integer> tmp = new ArrayList<Integer>();

        for (int i = 1; i <=rowIndex; i++)

        {

            for (int j = 0; j <= i; j++)

            {

                if (j == 0 || j == i) tmp.add(1);

                else

                {

                    tmp.add(ans.get(j-1) + ans.get(j));

                }

            }

            // update ans and clear tmp

            ans.clear();

            ans.addAll(tmp);

            tmp.clear();

        }

        return ans;

    }

}