LeetCode(33)-Pascal's Triangle II

题目：

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：

代码：

public class Solution {
public List<Integer> getRow(int rowIndex) {
List<Integer> pre = new ArrayList<Integer>();
List<Integer> next = new ArrayList<Integer>();
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;
}
}