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 # Brandes's Algorithm
 
-## Running
+## Building
 
     mkdir build
     cd build
     cmake ..
     make
+
+## Running
+
+    ./brandes <number threads> <input file> <output file>
+
+### Graph representation
+
+This implementation expects a simple, directed, unweighted graph with vertices
+labeled with integers.
+
+Sample input file:
+
+    0 2
+    2 0
+    2 3
+    2 4
+    3 2
+    3 5
+    3 6
+
+Here each line represents a directed edge from the first node to the second.
+
+The output will contain a line for each node with at least one out edge, of the
+form `<node> <BC[node]>`.  Thus for the above sample input, the output file
+should contain:
+
+    0 0
+    2 6
+    3 4