Data commit

Task/Kosaraju/Python/kosaraju-1.py

@@ -0,0 +1,40 @@
+def kosaraju(g):
+    class nonlocal: pass
+
+    # 1. For each vertex u of the graph, mark u as unvisited. Let l be empty.
+    size = len(g)
+
+    vis = [False]*size # vertexes that have been visited
+    l = [0]*size
+    nonlocal.x = size
+    t = [[]]*size   # transpose graph
+
+    def visit(u):
+        if not vis[u]:
+            vis[u] = True
+            for v in g[u]:
+                visit(v)
+                t[v] = t[v] + [u]
+            nonlocal.x = nonlocal.x - 1
+            l[nonlocal.x] = u
+
+    # 2. For each vertex u of the graph do visit(u)
+    for u in range(len(g)):
+        visit(u)
+    c = [0]*size
+
+    def assign(u, root):
+        if vis[u]:
+            vis[u] = False
+            c[u] = root
+            for v in t[u]:
+                assign(v, root)
+
+    # 3: For each element u of l in order, do assign(u, u)
+    for u in l:
+        assign(u, u)
+
+    return c
+
+g = [[1], [2], [0], [1,2,4], [3,5], [2,6], [5], [4,6,7]]
+print kosaraju(g)

Task/Kosaraju/Python/kosaraju-2.py

@@ -0,0 +1,36 @@
+def kosaraju(g):
+    size = len(g)
+    vis = [False] * size
+    l = [0] * size
+    x = size
+    t = [[] for _ in range(size)]
+
+    def visit(u):
+        nonlocal x
+        if not vis[u]:
+            vis[u] = True
+            for v in g[u]:
+                visit(v)
+                t[v].append(u)
+            x -= 1
+            l[x] = u
+
+    for u in range(size):
+        visit(u)
+    c = [0] * size
+
+    def assign(u, root):
+        if vis[u]:
+            vis[u] = False
+            c[u] = root
+            for v in t[u]:
+                assign(v, root)
+
+    for u in l:
+        assign(u, u)
+
+    return c
+
+
+g = [[1], [2], [0], [1, 2, 4], [3, 5], [2, 6], [5], [4, 6, 7]]
+print(kosaraju(g))