Merge 97fd1e4bea928602e21f28a049b008a5b5d6fb5c into 3ab4f89da6d560e3d641d09930eb8a16e053e870

other/breadthsearch.py

@@ -0,0 +1,31 @@
+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 person_is_seller(name):
+    return name[-1] =='m'
+
+def search(name):
+    search_queue = deque()
+    search_queue += graph[name]
+    searched = []
+    while search_queue:
+        person = search_queue.popleft()
+        if not person in searched:
+            if person_is_seller(person):
+                print person + " is a mango seller!"
+                return True
+            else:
+                search_queue += graph[person]
+                searched.append(person)
+    return False
+
+from collections import deque
+search("you")
+

other/dijkstra

@@ -0,0 +1,61 @@
+graph = {}
+infinity = float("inf")
+graph["start"] = {}
+graph["start"]["a"] = 6
+graph["start"]["b"] = 2
+graph["start"]["c"] = infinity
+
+graph["a"] = {}
+graph["a"]["c"] = 4
+graph["b"] = {}
+graph["b"]["a"] = 3
+graph["b"]["fin"] = infinity
+graph["b"]["c"] = 8
+
+graph["c"] = {}
+graph["c"]["fin"] = 6
+
+graph["fin"] = {}
+
+costs = {}
+costs["a"] = 6
+costs["b"] = 2
+costs["c"] = infinity
+costs["fin"] = infinity
+
+parents = {}
+parents["a"] = "start"
+parents["b"] = "start"
+parents["fin"] = "c"
+parents["c"] = "a"
+parents["c"] = "b"
+
+processed = []
+
+
+def find_lowest_cost_node(costs):
+    lowest_cost = float("inf")
+    lowest_cost_node = None
+    for node in costs:
+        cost = costs[node]
+        if cost < lowest_cost and node not in processed:
+            lowest_cost = cost
+            lowest_cost_node = node
+    return lowest_cost_node
+
+
+node = find_lowest_cost_node(costs)
+while node is not None:
+    cost = costs[node]
+    neighbors = graph[node]
+    for n in neighbors.keys():
+        new_cost = cost + neighbors[n]
+        if costs[n] > new_cost:
+            costs[n] = new_cost
+            parents[n] = node
+    processed.append(node)
+    node = find_lowest_cost_node(costs)
+
+print("Cost from the start to each node:")
+print(costs)
+print(parents)