Question

Given a non-negative integer numrows, generate the first numrows of pascal's triangle.

Answer 1

class Solution {

    public List<List<Integer>> generate(int numRows) {

        List<List<Integer>> res = new ArrayList<>();


        if(numRows == 0)

            return res;


        for(int i = 0; i < numRows; i++){

            for(int j = 0; j <= i; j++){

                if(j == 0) {

                    res.add(new ArrayList<>(i + 1));

                    res.get(i).add(1);

                }

                else if(j == i)

                    res.get(i).add(1);

                else

                    res.get(i).add(res.get(i-1).get(j-1) + res.get(i-1).get(j));

            }

        }


        return res;

    }

}