Add solution for exercise 12

Author: mmarx

12-betweenness.py

@@ -0,0 +1,30 @@
+#!/usr/bin/env python3
+
+import argparse
+from networkit import *
+from operator import itemgetter
+from collections import defaultdict
+
+
+if __name__ == '__main__':
+    parser = argparse.ArgumentParser(description=("Compute Betweenness for a given graph"))
+    parser.add_argument('input',
+                        help='path to input graph')
+    parser.add_argument('dict',
+                        help='path to input dict')
+    args = parser.parse_args()
+
+    graph = None
+    labels = {}
+
+    with open(args.dict, 'r') as dictfile:
+        for line in dictfile:
+            vertex, label = line.split(',', 1)
+            labels[int(vertex)] = label.strip()[1:-1]
+
+    graph = readGraph(args.input, Format.METIS)
+    betweenness = centrality.Betweenness(graph)
+    ranking = betweenness.run().ranking()
+
+    for vertex, rank in ranking[:20]:
+        print('{}. {}'.format(rank, labels[int(vertex + 1)]))