init

3H.py

@@ -0,0 +1,26 @@
+import sys
+
+input_data = sys.stdin.read().split()    
+N = int(input_data[0])
+edges = []
+idx = 1
+for i in range(N):
+    for j in range(N):
+        w = int(input_data[idx])
+        idx += 1
+        if w != 100000:
+            edges.append((i, j, w))
+d = [0] * N
+for _ in range(N - 1):
+    for u, v, w in edges:
+        if d[u] + w < d[v]:
+            d[v] = d[u] + w
+flag = False
+for u, v, w in edges:
+    if d[u] + w < d[v]:
+        flag = True
+        break
+if flag:
+    print("YES")
+else:
+    print("NO")