pascals triangle

/*
I can use two pointers to make this happen,

The ith entry of the row contains 'i' elements

the first and last entries of the list is '1'

1 -> 1
2 -> 2
3 -> 3
4 -> 4

*/

class Solution {
public:
    vector<vector<int>> generate(int numRows) {
        // Create the triangle
        vector<vector<int>> pascal;

        // Iterate over the triangle to fill it
        for(int k = 0; k < numRows; k++) {
            // Create a new row, with first and last entry as 1
            vector<int> row = vector<int>(k+1, 1);

            // push the row
            pascal.emplace_back(row);

            // If length is greater than 2
            if(k >= 2) {
                // Use two pointers to fill the array,
                // left will start for the 0th index, right will go upto the last index
                int l = 0, r = 1;
                while(r != k) {
                    pascal[k][l+1] = pascal[k-1][l] + pascal[k-1][r];
                    l++;
                    r++;
                }
            }
        }
        return pascal;
    }
};