Pascal's Triangle - LeetCode

I have not done any coding problem recently. Here is simple problem with a simple solution. https://leetcode.com/problems/pascals-triangle/

Given numRows, generate the first numRows of Pascal's triangle.
For example, given numRows = 5,
Return

[
     [1],
    [1,1],
   [1,2,1],
  [1,3,3,1],
 [1,4,6,4,1]
]

The idea here is every row in the triangle is generated based on the row above it. For example, the 3rd row [1, 2, 1] can be generated by going through each item in the row [1, 1], add pre number or 0 for the first item and itself, so it will be 0+1 = 1, 1+1=2, then append 1 in the list.

The code is pretty straightforward.

	public class Solution {
	public List<List<Integer>> generate(int numRows) {
	List<List<Integer>> list = new ArrayList<>();
	for(int i = 1; i<=numRows; i++){
	List<Integer> curr = new ArrayList<>();
	if(!list.isEmpty()){
	int pr = 0;
	for(int num : list.get(list.size()-1)){
	curr.add(num+pr);
	pr = num;
	}
	}
	curr.add(1);
	list.add(curr);
	}
	return list;
	}
	}

view raw PascalTriangle.java hosted with ❤ by GitHub