119. Pascal's Triangle II

Given a non-negative index k where k ≤ 33, return the k index row of the Pascal’s triangle.
Note that the row index starts from 0.

In Pascal’s triangle, each number is the sum of the two numbers directly above it.
Example: Input: 3 Output: [1,3,3,1]Follow up:
Could you optimize your algorithm to use only O(k) extra space?

Runtime: 0 ms, faster than 100.00% of C++ online submissions for Pascal’s Triangle II.

class Solution {
public:
    vector<int> getRow(int rowIndex) {
        vector <int> row(rowIndex + 1);
        row[0] = 1;
        for (int i = 0; i <= rowIndex; i++) {
            for (int j = i; j > 0; j--)
            {
                row[j] = row[j] + row[j - 1];
            }
        }
        return row;
    }
};