Pascal's Triangle

public class Solution {
public List<List<Integer>> generate(int numRows) {
List<List<Integer>> result = new ArrayList<List<Integer>>();
if (numRows < 1) {
return result;
}
int currentLevel = 1;
List<Integer> level = new ArrayList<Integer>();
while (currentLevel <= numRows) {
level.add(1);
for (int i = currentLevel - 2; i > 0; i--) {
level.set(i, level.get(i) + level.get(i - 1));
}
result.add(new ArrayList<Integer>(level));
currentLevel++;
}
return result;
}
}