code for chapter 6

06_breadth-first_search/python/01_breadth-first_search.py

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+from collections import deque
+
+def person_is_seller(name):
+      return name[-1] == 'm'
+
+graph = {}
+graph["you"] = ["alice", "bob", "claire"]
+graph["bob"] = ["anuj", "peggy"]
+graph["alice"] = ["peggy"]
+graph["claire"] = ["thom", "jonny"]
+graph["anuj"] = []
+graph["peggy"] = []
+graph["thom"] = []
+graph["jonny"] = []
+
+def search(name):
+    search_queue = deque()
+    search_queue += graph[name]
+    # This array is how you keep track of which people you've searched before.
+    searched = []
+    while search_queue:
+        person = search_queue.popleft()
+        # Only search this person if you haven't already searched them.
+        if not person in searched:
+            if person_is_seller(person):
+                print person + " is a mango seller!"
+                return True
+            else:
+                search_queue += graph[person]
+                # Marks this person as searched
+                searched.append(person)
+    return False
+
+search("you")