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  1. def main():
  2.     #fin = open("flip.in","r")
  3.     #nm = [int(i) for i in fin.readline().split()]
  4.     nm = [int(i) for i in input().split()]
  5.     n = nm[0]
  6.     m = nm[1]
  7.     matrix = [list(map(int, input().split())) for _ in range(n)]
  8.     #print(matrix)
  9.     sum_max = 0
  10.  
  11.     def solve_flip(stack):
  12.  
  13.         #declare the variable as nonlocal to modify the outer variable
  14.         nonlocal sum_max
  15.         #declare a variable that holds local stotal
  16.         stotal = 0
  17.         #make a copy of the matrix
  18.         matrix2 = [row[:] for row in matrix]
  19.  
  20.         for line in stack:
  21.             for j in range(m):
  22.                 matrix2[line][j] *= -1
  23.  
  24.         for j in range(m):
  25.             s = 0
  26.             for i in range(n):
  27.                 s += matrix2[i][j]
  28.             if s<0:
  29.                s *= -1
  30.             stotal += s
  31.  
  32.         if sum_max < stotal:
  33.             sum_max = stotal
  34.  
  35.     size = 2**n
  36.     mask = 1
  37.     for i in range(1,size):
  38.         #empty stack
  39.         stack = []
  40.         for j in range(n):
  41.             if (mask<<j)&i:
  42.                 #print(j, end = " ")
  43.                 stack.append(j)
  44.         solve_flip(stack)
  45.     #fout = open("flip.out","w")
  46.     print(sum_max)
  47.     #fout.write(str(sum_max))
  48. main()
Success #stdin #stdout 0.04s 9896KB
comments (?)
stdin
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5 3
4 -2 2
3 -1 5
2 0 -3
4 1 -3
5 -3 2
stdout
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28
https://ideone.com/4Gfh49
Flip Problem
language:
Python 3 (python  3.9.5)
created:
145 days ago
visibility:
secret

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