added README and landmark generation helper

utils/generate_landmarks.py

@@ -0,0 +1,17 @@
+#!/usr/bin/env python3
+
+from os import system
+from sys import argv, exit
+
+if len(argv) != 3:
+    print(f"usage: {argv[0]} <graph> <output_prefix>")
+    exit(1)
+
+graph = argv[1]
+output = argv[2]
+
+for i in range(2, 7):
+    num = 2**i
+
+    system(f"cargo run --release --bin=gen_landmarks_greedy -- --input={graph} --output={output}_greedy_{ num }.bin --amount { num }")
+    system(f"cargo run --release --bin=gen_landmarks_random -- --input={graph} --output={output}_random_{ num }.bin --amount { num }")