118. Pascal's 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] ]

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public class Solution { public List<List<Integer>> generate(int numRows) { List<List<Integer>> re=new ArrayList<List<Integer>>(); if(numRows==0) return re; List<Integer> list=new ArrayList<Integer>(); list.add(1); re.add(list); for(int i=1;i<numRows;++i){ List<Integer> temp=new ArrayList<Integer>(); temp.add(1); for(int j=1;j<i;++j) temp.add(re.get(i-1).get(j-1)+re.get(i-1).get(j)); temp.add(1); re.add(temp); } return re; } }