https://leetcode.com/problems/pascals-triangle-ii/

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