toposort

TopologicalSort.py

@@ -0,0 +1,27 @@
+def topsort(g,vtx):
+    degree = [0]*vtx
+    for node in g:
+        for adjnode in g[node]:
+            degree[adjnode]+=1
+
+
+    bfs = [i for i in range(vtx) if degree[i] == 0]
+    for node in bfs:
+        for adjnode in g[node]:
+            degree[adjnode]-=1
+            if degree[adjnode] == 0:
+                bfs.append(adjnode)
+    return bfs
+
+
+from collections import defaultdict
+g = defaultdict(list)
+vtx,e = map(int,input().split())
+for i in range(e):
+    u,v = map(str,input().split())
+    u = ord(u) - ord('A')
+    v = ord(v) - ord('A')
+    g[u].append(v)
+topSort = topsort(g,vtx)
+topSort = [chr(i+65) for i in topSort]
+print(topSort)