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;
}
}