fix: diffing but not actually

Author: VanillaViking

competition/13-time-traveler/run.sh

@@ -1,4 +1,7 @@
 #!/bin/bash
 
-g++ --std=c++20 src/main.cpp -o time-traveler &&
+if [ ! -f time-traveler ]; then
+  g++ --std=c++20 src/main.cpp -o time-traveler
+fi
+
 ./time-traveler $1 $2