class Solution:

# @return a list of lists of integers

def generate(self, numRows):

if numRows == 0:

return []

r = [1]

l = []

l.append([1])

for i in range(1,numRows):

```
r.append(0)
for j in range(1,i+1)[::-1]:
r[j] = r[j] + r[j-1]
l.append(str(r))
return l
```