Solutions for day 9.

day9-input.txt

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+Tristram to AlphaCentauri = 34
+Tristram to Snowdin = 100
+Tristram to Tambi = 63
+Tristram to Faerun = 108
+Tristram to Norrath = 111
+Tristram to Straylight = 89
+Tristram to Arbre = 132
+AlphaCentauri to Snowdin = 4
+AlphaCentauri to Tambi = 79
+AlphaCentauri to Faerun = 44
+AlphaCentauri to Norrath = 147
+AlphaCentauri to Straylight = 133
+AlphaCentauri to Arbre = 74
+Snowdin to Tambi = 105
+Snowdin to Faerun = 95
+Snowdin to Norrath = 48
+Snowdin to Straylight = 88
+Snowdin to Arbre = 7
+Tambi to Faerun = 68
+Tambi to Norrath = 134
+Tambi to Straylight = 107
+Tambi to Arbre = 40
+Faerun to Norrath = 11
+Faerun to Straylight = 66
+Faerun to Arbre = 144
+Norrath to Straylight = 115
+Norrath to Arbre = 135
+Straylight to Arbre = 127

day9.py

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+import re
+import fileinput
+
+dist = {}
+visited = set()
+
+def computeMinDistance(startPoint):
+    visited.add(startPoint)
+
+    if len(dist) == len(visited):
+        maximum = 0
+        minimum = 0
+    else:
+        minimum = None
+        maximum = 0
+
+    for i in dist[startPoint]:
+        if i in visited:
+            continue
+
+        shortest, longest = computeMinDistance(i)
+
+        if shortest is not None:
+            shortest += dist[startPoint][i]
+            longest += dist[startPoint][i]
+
+            if minimum is None:
+                minimum = shortest
+                maximum = longest
+            else:
+                minimum = min(minimum, shortest)
+                maximum = max(maximum, longest)
+
+    visited.remove(startPoint)
+
+    return minimum, maximum
+
+
+
+linePattern = re.compile(r"(\w+) to (\w+) = (\d+)")
+
+for line in fileinput.input():
+    match = linePattern.match(line)
+    if match.group(1) not in dist:
+        dist[match.group(1)] = {}
+
+    if match.group(2) not in dist:
+        dist[match.group(2)] = {}
+
+    dist[match.group(1)][match.group(2)] = int(match.group(3))
+    dist[match.group(2)][match.group(1)] = int(match.group(3))
+
+minimum = None
+possible = []
+for i in dist:
+    shortest, longest = computeMinDistance(i)
+
+    if shortest is not None:
+        possible.append(shortest)
+        possible.append(longest)
+
+print "Shortest path is", min(possible)
+print "Longest path is", max(possible)