implementing digraph generation

src/main.rs

@@ -13,7 +13,7 @@ fn main() -> std::io::Result<()> {
 
     // examples::stats()?;
 
-    examples::freq()?;
+    // examples::freq()?;
 
     // examples::hoop()?;
 
@@ -25,5 +25,7 @@ fn main() -> std::io::Result<()> {
 
     // examples::fast_freq()?;
 
+    examples::digraph()?;
+
     Ok(())
 }