LeetCode 119. Pascal's Triangle II

Given an index k, return the kth row of the Pascal's triangle.

For example, given k = 3,
Return [1,3,3,1].

Note:
Could you optimize your algorithm to use only O(k) extra space?

和上一题基本思路一样

java代码：

public List getRow(int rowIndex) {
        List> pascal = new ArrayList>();
        ArrayList row = new ArrayList();
        for (int i = 0; i < rowIndex+1; i++) {
            row.add(0, 1);
            for (int j = 1; j < row.size() - 1; j++) {
                row.set(j, row.get(j) + row.get(j + 1));
            }
            pascal.add(new ArrayList(row));
        }
        return pascal.get(pascal.size()-1);
    }