Finding integer distance between two intervals

Question

I'm looking for an easy way to find the minimum distance between two integer intervals using python. For example, the minimum between [0,10] and [12,20] would be 2. If the two intervals overlap in any way, the distance would be 0.

Any suggestions on an easy way to do this? I can't help but think there must be a clean, 'pythonic' way to get at this question.

Answer 1

def solve(r1, r2):
     # sort the two ranges such that the range with smaller first element
     # is assigned to x and the bigger one is assigned to y
     x, y = sorted((r1, r2))

     #now if x[1] lies between x[0] and y[0](x[1] != y[0] but can be equal to x[0])
     #then the ranges are not overlapping and return the differnce of y[0] and x[1]
     #otherwise return 0 
     if x[0] <= x[1] < y[0] and all( y[0] <= y[1] for y in (r1,r2)):
        return y[0] - x[1]
     return 0
... 
>>> solve([0,10],[12,20])
2
>>> solve([5,10],[1,5])
0
>>> solve([5,10],[1,4])
1