feat: 96. 城市间货物运输 III增加python解法

problems/kamacoder/0096.城市间货物运输III.md

@@ -703,6 +703,42 @@ public class Main {
 ```
 
 ### Python
+```python
+def main():
+    # 輸入
+    n, m = map(int, input().split())
+    edges = list()
+    for _ in range(m):
+        edges.append(list(map(int, input().split() )))
+    
+    start, end, k = map(int, input().split())
+    min_dist = [float('inf') for _ in range(n + 1)]
+    min_dist[start] = 0
+    
+    # 只能經過k個城市，所以從起始點到中間有(k + 1)個邊連接
+    # 需要鬆弛(k + 1)次
+    
+    for _ in range(k + 1):
+        update = False
+        min_dist_copy = min_dist.copy()
+        for src, desc, w in edges:
+            if (min_dist_copy[src] != float('inf') and 
+            min_dist_copy[src] + w < min_dist[desc]):
+                min_dist[desc] = min_dist_copy[src] + w
+                update = True
+        if not update:
+            break
+    # 輸出
+    if min_dist[end] == float('inf'):
+        print('unreachable')
+    else:
+        print(min_dist[end])
+            
+            
+
+if __name__ == "__main__":
+    main()
+```
 
 ### Go