Special elements in a matrix

special_elements.py

# Complete the countSpecialElements function below.
def countSpecialElements(matrix):
    items = set()
    for m, row in enumerate(matrix):
        min_i, max_i, solution = min_max_in_list(row)
        if not solution:
            return -1
        # add as row_col
        items.add('%d_%d' % (m, min_i))
        items.add('%d_%d' % (m, max_i))
    
    matrix = [[matrix[j][i] for j in range(len(matrix))] for i in range(len(matrix[0]))] 
    # print matrix
    for n, col in enumerate(matrix):
        min_i, max_i, solution = min_max_in_list(col)
        if not solution:
            return -1
        # add as row_col
        items.add('%d_%d' % (min_i, n))
        items.add('%d_%d' % (max_i, n))
    print items
    return len(items)

    
def min_max_in_list(lst): 
    """
    Return the index of min and max in the given list
    """
    max = lst[0]
    min = max
    min_i, max_i = 0, 0 # index of min and max
    for i in range(len(lst)):
        if min > lst[i]:
            min = lst[i]
            min_i = i
        if max < lst[i]:
            max = lst[i]
            max_i = i
    if lst.count(max)>1 or lst.count(min)>1:
        return 0, 0, false
    return min_i, max_i, true