I wrote the following code for the problem Sums in a Triangle. It is working in my computer but here on codechef I am getting NZEC. The input isn’t that big then why this error?

```
import sys
from itertools import islice
def p():
cases = int(sys.stdin.readline())
for case in xrange(cases):
height = int(sys.stdin.readline())
triangle = [map(int, i.split()) for i in islice(sys.stdin,height)]
for i in xrange(1, height):
cur_row = triangle[i]
cur_row[0] += prev_row[0]
cur_row[len(cur_row) - 1] += prev_row[len(prev_row) - 1]
for j in xrange(1, len(cur_row) - 1):
if(prev_row[j - 1] > prev_row[j]):
cur_row[j] += prev_row[j - 1]
else:
cur_row[j] += prev_row[j]
prev_row = cur_row
print max(prev_row)
p()
```