class Solution:
# @param A : list of list of integers
# @return a list of list of integers
def diagonal(self, A):
row_len = len(A)
col_len = len(A[0])
B = []
start_row = 0
start_col = 0
while True:
C = []
j = 0
curr_row = start_row
for j in range(start_col, col_len):
C.append(A[j][curr_row])
if curr_row == 0:
break
curr_row -= 1
if C:
B.append(C)
if start_row < row_len - 1:
start_row += 1
else:
start_col += 1
if start_col > (col_len - 1):
break
return(B)