LeetCode(33)-Pascal's Triangle II

題目：

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

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

思路：

代碼：

public class Solution {
    public List getRow(int rowIndex) {
        List pre = new ArrayList();
        List next = new ArrayList();
        pre.add(1);
        if(rowIndex == 0){
            return pre;
        }
        for(int i = 1;i < rowIndex+1;i++){
            next.add(1);
            for(int a = 1;a < i;a++){
                next.add(pre.get(a-1)+pre.get(a));
            }
            next.add(1);
            pre.clear();
            for(int o =0;o < next.size();o++ ){
                pre.add(next.get(o));
            }
            next.clear();
        }
        return pre;
    }
}