Snail Sort

Given an n x n array, return the array elements arranged from outermost elements to the middle element, traveling clockwise.

array = [[1,2,3],         [4,5,6],         [7,8,9]]snail(array) #=> [1,2,3,6,9,8,7,4,5]

For better understanding, please follow the numbers of the next array consecutively:

array = [[1,2,3],         [8,9,4],         [7,6,5]]snail(array) #=> [1,2,3,4,5,6,7,8,9]

This image will illustrate things more clearly:

NOTE: The idea is not sort the elements from the lowest value to the highest; the idea is to traverse the 2-d array in a clockwise snailshell pattern.

NOTE 2: The 0x0 (empty matrix) is represented as [[]]我好像最后还是没考虑空矩阵的处理。。。啊啊啊啊，路漫漫啊


 1 helper = PaginationHelper([‘a‘,‘b‘,‘c‘,‘d‘,‘e‘,‘f‘], 4) 2 helper.page_count # should == 2 3 helper.item_count # should == 6 4 helper.page_item_count(0)  # should == 4 5 helper.page_item_count(1) # last page - should == 2 6 helper.page_item_count(2) # should == -1 since the page is invalid 7  8 # page_ndex takes an item index and returns the page that it belongs on 9 helper.page_index(5) # should == 1 (zero based index)10 helper.page_index(2) # should == 011 helper.page_index(20) # should == -112 helper.page_index(-10) # should == -1 because negative indexes are invalid

1 #方案12 def snail(array):3     return list(array[0]) + snail(zip(*array[1:])[::-1]) if array else []

 1 #方案2 2 def snail(array): 3     ret = [] 4     if array and array[0]: 5         size = len(array) 6         for n in xrange((size + 1) // 2): 7             for x in xrange(n, size - n): 8                 ret.append(array[n][x]) 9             for y in xrange(1 + n, size - n):10                 ret.append(array[y][-1 - n])11             for x in xrange(2 + n, size - n + 1):12                 ret.append(array[-1 - n][-x])13             for y in xrange(2 + n, size - n):14                 ret.append(array[-y][n])15     return ret

#方案3def snail(array):    a = []    while array:        a.extend(list(array.pop(0)))        array = zip(*array)        array.reverse()    return a

 1 #为方便本地调试，加了很多 print，提交的时候需要注释掉 2 def snail(array): 3     ans = [] 4     if len(array) == 1: # preven "index out of range"!!! 5         ans = array[0] 6         #print ans 7         return ans 8     len_row = len(array) - 1 9     len_col = len(array[1]) - 110     all = (len_row + 1) * (len_col +1 )11     #print len_col12     over_row = 013     over_col = 014     while over_col <= len_col/2:15         row = over_row  # current row16         col = over_col17         while over_col <= col < len_col - over_col:18             now = array[row][col]19             ans.append(now)20             col += 121             #print ‘now == ‘, now22         #print ‘this row over, col ==‘, col23 24         while over_row <= row < len_row - over_row :25             now = array[row][col]26             ans.append(now)27             row += 128             #print ‘now == ‘, now29         #print ‘this col over, row ==‘, row30 31         while over_col < col <= len_col - over_col:32             now = array[row][col]33             ans.append(now)34             col -= 135             #print ‘now == ‘, now36         #print ‘this reverse row over, col ==‘, col37 38         while over_row < row <= len_row - over_row:39             now = array[row][col]40             ans.append(now)41             row -= 142             #print ‘now == ‘, now43     #print ‘this reverse col over, col ==‘, row44 45         over_row += 146         over_col += 147         #print ‘print over_row == ‘, over_row, ‘print over_col == ‘, over_col48     if len(ans) < all:49         last = int(len_row/2)50         ans.append(array[last][last])51     #print ans52     return ans