The Stone Wall The Stone Wall
Simple
RU JA English
Finding the castle with a map and a compass was a piece of cake. Moreover, when you’ve inspected the surroundings through the spyglass, you spotted a small sailing yacht a few kilometers from the place where you were washed ashore. It has probably belonged to other treasure hunters who have failed to leave the island. After checking it out you’ve came to a conclusion that yacht is in a pretty good shape and with the fair-wind you’ll have no problems returning home. Well, in any case, you’ll have less problems - now you just have to find the Cube.

As I’ve said before, the lord who used to live here, highly appreciated the solitude, therefore it’s not surprising that the estate was surrounded by a very high and thick stone wall. Fortunately, you’ve foreseen this and took some explosives with you (I don’t even want to know where you got it from). However, it’s unlikely that this modest reserve will suffice to blow up the wall just anywhere - it’d be better to act for sure and find the most vulnerable place.

As input you'll get a multiline string consists of '0' and '#' - a view of a stone wall from above. The '#' will show the stone part of the wall and the '0' will show the empty part. The relative location of you and the wall is as follows: you look at the array from the bottom of it.
Your task is to find the index of the place where the wall is the narrowest (as shown at the picture below). The width of the wall is the height of the columns of the array (multiline string). If there are several such places, return the index of leftmost. Index starts from 0.

Input: Array represents the stone wall.

Output: List of the weakest spots.

Example:

stone_wall('''
##########
####0##0##
00##0###00
''') == 4

How it is used: For the architecture analisys.

Precondition:
3x3 <= array size <= 10x10