PascalTri.java

import java.util.ArrayList;
import java.util.*;
public class PascalTri {
 public List<List<Integer>> generate(int numRows) {
 List<List<Integer>> result = new ArrayList<>();
 // compute the first numRows of Pascal's triangle
 for(int i = 0; i < numRows; i++){
 List<Integer> innerList = new ArrayList<>(i+1);
 result.add(innerList);
 innerList.add(0, 1);
 if(i>0) innerList.add(1, 1);
 int j = 1;
 if(i>1){
 while(j < i){
 innerList.add(j, result.get(i-1).get(j-1) + result.get(i-1).get(j));
 j++;
 }
 }
 }
 return result;
 }
}