further performance improvement

still room for optimisations; making deep copy because iterator is not
modifiable in for loops

src/vigenere/break_vig.py

@@ -18,7 +18,7 @@ def probe(key, substrings, words):
 
 
 def remove_crap_from_list(tree, max_depth, thr):
-    best = [0 for x in range(max_depth+1)]
+    best = [-x * thr for x in range(max_depth+2)]
     for key, val in tree.items():
         if val > best[len(key)]:
             best[len(key)] = val
@@ -26,8 +26,10 @@ def remove_crap_from_list(tree, max_depth, thr):
     import copy
     tmp = copy.copy(list(tree.items()))
     for key, val in tmp:
-        if val < (best[len(key)] - thr):
-            del tree[key]
+        for i in range(len(key), max_depth+1):
+            if val < (best[i] - thr + (i-len(key))*thr*1.5):
+                del tree[key]
+                break
 
 
 def crack(substrings, words):
@@ -35,15 +37,11 @@ def crack(substrings, words):
     while tree:
         curr = [key for key, val in sorted(
             tree.items(), key=lambda ele: ele[1])][-1]
-        print(curr)
         if len(curr) == len(substrings[0]):
             return curr
         del tree[curr]
         tree.update(probe(curr, substrings, words))
-        print(tree)
         remove_crap_from_list(tree, len(substrings[0]), 10)
-        print(tree)
-        print()
 
 
 if __name__ == "__main__":