cc 1.7

setZeroes.py

1.7  Write an algorithm such that if an element in an MxN matrix is 0, its entire row and column are set to 0.

# deal matrix as a list


def listIndex(x, y, n):
    return y + x * n

def toList(matrix, m, n):
    global listm
    listm = list()
    #write matrix to list
    for i in range(n):
        for j in range(m):
           # listm.insert(listIndex(i, j ,n),matrix[i][j])  
            listm.append(matrix[i][j])
    print ('original matrix:', listm)
    return listm

    
def checkzeroes(matrix, m, n):
    
    global row
    row = [False for i in range(n)]
    global col
    col = [False for i in range(m)]
   
    for i in range (n):
        for j in range (m):
            if matrix[i][j] == 0:
                row[i] = True
                col[j] = True
    print row, col
    return (row, col) 
    
def setzeroes(matrix, m, n):
    
    toList(matrix, m, n)
    checkzeroes(matrix, m, n)

    for i in range(n):
        for j in range(m):
            if (row[i] or col[j]):
                listm[listIndex(i, j, n)] = 0
    
    return listm

#test case
                
m = 3
n = 3
matrix = [(1,2,3), (2,5,8), (0,3,6)]
setzeroes(matrix, m, n)
print 'After setzeroes:'
for i in range(m*n):
    print (listm[i]),
    if (i+1) % m == 0:
        print('\n')