--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/python/example/possibilities.py	Sun Jul 03 18:33:09 2016 -0700
@@ -0,0 +1,104 @@
+#!/usr/bin/env python
+
+# imports
+import argparse
+import sys
+import time
+from pprint import pprint
+
+costs = {1:1,
+         7:3,
+         30:25}
+
+A = [1, 2, 4, 5, 7, 29, 30]
+
+#A = [3, 7, 10]
+
+#A=[1,2,3]
+
+def possibilities(A):
+    possibilities = [[(1, date) for date in A]]
+    for_consideration = [0]
+    while True:
+        if not for_consideration:
+            break
+        _for_consideration = []
+        for item in for_consideration:
+            basis = possibilities[item][:]
+            tickets = [i[0] for i in basis]
+            if set(tickets) == set([7]):
+                continue
+            index = 0
+            potential = []
+            while True:
+                try:
+                    pos = tickets.find(1, index)
+                except ValueError:
+                    break
+                potential = basis[:]
+                potential[pos] = (7, basis[pos][-1])
+
+        try:
+            while A[index] < date+6:
+                index += 1
+        except IndexError:
+            pass
+
+    return possibilities
+
+def fill_space(A, spans):
+    """
+    A -- the space to be filled
+    spans -- the discrete length of each space
+    """
+    if not A:
+        return []
+
+    A = sorted(A)
+
+    possibilities = []
+
+    # [(ticket_value, index_into_A)]
+    working_set = [[(value, 0)] for value in spans]
+    # print "working set"
+    # pprint(working_set)
+    while working_set:
+        item = working_set.pop()
+        last_span, index = item[-1]
+        last_date = A[index]
+        e = None
+        index += 1
+        try:
+            while last_date + last_span > A[index]:
+                print ('index: {}'.format(index))
+                index += 1
+        except IndexError as e:
+            possibilities.append(item)
+            continue
+
+        # print "item:"
+        # pprint(item)
+        extension = [item[:] + [(span, index)]
+                     for span in spans]
+
+        working_set.extend(extension)
+
+    # fill possibility indices with dates
+    retval = [[(A[index], span) for span, index in possibility]
+              for possibility in possibilities]
+    return retval
+
+
+def cost(A, spans=(30,)):
+
+    # determine possibility spaces
+    spaces = fill_space(A, spans=spans)
+
+    # determine costs
+
+if __name__ == '__main__':
+
+    parser = argparse
+    spans = costs.keys()
+
+    pprint (fill_space(A, spans))