new_contents: class Solution:
      # @param matrix, a list of lists of integers
      # RETURN NOTHING, MODIFY matrix IN PLACE.
  
      def setZeroes(self, matrix):
          if not matrix:
              return
          n = len(matrix)
          if n == 0:
              return
          m = len(matrix[0])
          pos = None
          for i in xrange(n):
              for j in xrange(m):
                  if matrix[i][j] == 0:
                      if pos:
                          matrix[i][pos[1]] = 0
                          matrix[pos[0]][j] = 0
                      else:
                          pos = (i, j)
          if not pos:
              return
          for i in xrange(n):
              if i == pos[0]:
                  continue
              for j in xrange(m):
                  if j == pos[1]:
                      continue
                  if matrix[pos[0]][j] == 0 or matrix[i][pos[1]] == 0:
                      matrix[i][j] = 0
  
          for i in xrange(n):
              matrix[i][pos[1]] = 0
          for j in xrange(m):
              matrix[pos[0]][j] = 0
  
subject: add solution for Set Matrix Zeroes