```
class Solution:
# @param triangle, a list of lists of integers
# @return an integer
def minimumTotal(self, triangle):
if triangle is None:
return
t_len = len(triangle)
res = triangle[-1][:]
for lv in triangle[-2::-1]:
for i in range(len(lv)):
res[i] = min(res[i]+lv[i],res[i+1]+lv[i])
return res[0]
```