# Help with Memory Limit Exceeded

• Is the problem of "column()" function?
Thanks!

``````def column(matrix,i):
return [row[i] for row in matrix]

class Solution:
# @param prices, a list of integer
# @return an integer
def maxProfit(self, prices):
if len(prices) <= 1:
return 0

profits=[[0 for i in range(len(prices))] for j in range(len(prices))]
for j in range(len(prices)):
for i in range(j):
profits[j][i] = prices[i] - prices[j]

# one transaction
maxprofit=[max(max(profits))]

# two transaction one before day k, one after day k
#profit1=max(max(tocolumn(profits[:k],k)))
profit1=[0]
for i in range(1,len(prices)):            #sell day
if max(profits[i]) > profit1[-1]:
profit1.append(max(profits[i]))
else:
profit1.append(profit1[-1])

#profit2=max(max(fromcolumn(profits[k:],k)))
profit2=[0]
for i in range(len(prices)-2,-1,-1):
if max(column(profits,i)) > profit2[-1]:
profit2.append(max(column(profits,i)))
else:
profit2.append(profit2[-1])
profit2.reverse()

for i in range(len(profit1)):
maxprofit.append(profit1[i]+profit2[i])

return max(maxprofit)``````

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