network time delay - pending...

ProblemSolving/networkTimeDelay/network.py

@@ -0,0 +1,54 @@
+class Solution(object):
+    def networkDelayTime(self, times, N, K):
+        """
+        :type times: List[List[int]]
+        :type N: int
+        :type K: int
+        :rtype: int
+        """
+
+        # Create a relation of all the nodes, like a dictionary
+        relation = {}
+        for time in times:
+            if time[0] not in relation:
+                relation[time[0]] = {}
+                relation[time[0]][time[0]] = 0
+
+            # Source Node = Destination Node = Time
+            relation[time[0]][time[1]] = time[2]
+
+        """
+        # Logic to construct complete relationship from each node to all nodes (incomplete)
+        # we dont need this in this problem as we are already given the source node K
+        for key in relation.keys():
+            temp = relation[key][:]
+            for key1 in temp:
+                if key1 in relation:
+                    for key2 in relation[key1]:
+                        relation[key][key2] = relation[key1][key2]
+        """
+
+        #print relation
+
+        # For "k" destination try to navigate through all nodes
+        distances = [0]*N
+        for i in range(1,N+1):
+            # Direct distance from K
+            if K in relation and i in relation[K].keys():
+                distances[i-1] = relation[K][i]
+            else:
+                if K in relation:
+                    for key in relation[K].keys():
+                        if key in relation:
+                            if i in relation[key]:
+                                distances[i-1] = relation[key][i] + distances[key-1]
+
+        if max(distances) == 0:
+            return -1
+
+        print distances
+        return max(distances)
+
+
+
+