Create 743-Network-Delay-Time.py

neetcode-gh · web-flow · commit 246e49deb3a2 · 2022-03-27T23:51:34.000-07:00
diff --git a/743-Network-Delay-Time.py b/743-Network-Delay-Time.py
@@ -0,0 +1,22 @@
+class Solution:
+    def networkDelayTime(self, times: List[List[int]], n: int, k: int) -> int:
+        edges = collections.defaultdict(list)
+        for u, v, w in times:
+            edges[u].append((v, w))
+        
+        minHeap = [(0, k)]
+        visit = set()
+        t = 0
+        while minHeap:
+            w1, n1 = heapq.heappop(minHeap)
+            if n1 in visit:
+                continue
+            visit.add(n1)
+            t = max(t, w1)
+            
+            for n2, w2 in edges[n1]:
+                if n2 not in visit:
+                    heapq.heappush(minHeap, (w1 + w2, n2))
+        return t if len(visit) == n else -1
+    
+        # O(E * logV)
