add topological

algs4/depth_first_order.py

@@ -40,7 +40,7 @@ def __init__(self, G):
         self.post = Queue()
         for w in range(G.V):
             if not self.marked[w]:
-                self.dfs(g, w)
+                self.dfs(G, w)
 
     def dfs(self, G, v):
         self.pre.enqueue(v)

algs4/symbol_digraph.py

@@ -0,0 +1,94 @@
+"""
+   Execution:    python symbol_graph.py filename.txt delimiter
+   Data files:   https://algs4.cs.princeton.edu/41graph/routes.txt
+                 https://algs4.cs.princeton.edu/41graph/movies.txt
+                 https://algs4.cs.princeton.edu/41graph/moviestiny.txt
+                 https://algs4.cs.princeton.edu/41graph/moviesG.txt
+                 https://algs4.cs.princeton.edu/41graph/moviestopGrossing.txt
+
+   %  python symbol_graph.py routes.txt " "
+   JFK
+      MCO
+      ATL
+      ORD
+   LAX
+      PHX
+      LAS
+
+   % python symbol_graph.py movies.txt "/"
+   Tin Men (1987)
+      Hershey, Barbara
+      Geppi, Cindy
+      Jones, Kathy (II)
+      Herr, Marcia
+      ...
+      Blumenfeld, Alan
+      DeBoy, David
+   Bacon, Kevin
+      Woodsman, The (2004)
+      Wild Things (1998)
+      Where the Truth Lies (2005)
+      Tremors (1990)
+      ...
+      Apollo 13 (1995)
+      Animal House (1978)
+
+
+   Assumes that input file is encoded using UTF-8.
+   % iconv -f ISO-8859-1 -t UTF-8 movies-iso8859.txt > movies.txt
+
+ """
+
+from algs4.st import ST
+from algs4.digraph import Digraph
+
+
+class SymbolDigraph:
+
+    def __init__(self, stream, sp):
+        self.st = ST()
+
+        for line in open(stream):
+            a = line.strip().split(sp)
+            for i in range(len(a)):
+                if not self.st.contains(a[i]):
+                    self.st.put(a[i], self.st.size())
+
+        self.keys = ["" for _ in range(self.st.size())]
+        for key in self.st.keys():
+            self.keys[self.st.get(key)] = key
+
+        self.G = Digraph(self.st.size())
+        for line in open(stream):
+            a = line.strip().split(sp)
+            v = self.st.get(a[0])
+            for i in range(1, len(a)):
+                self.G.add_edge(v, self.st.get(a[i]))
+
+    def contains(self, s):
+        return self.st.contains(s)
+
+    def index(self, s):
+        return self.st.get(s)
+
+    def name(self, v):
+        return self.keys[v]
+
+    def digraph(self):
+        return self.G
+
+
+if __name__ == "__main__":
+    import sys
+    filename, delimiter = sys.argv[1], sys.argv[2]
+    sg = SymbolDigraph(filename, delimiter)
+    graph = sg.digraph()
+
+    for line in sys.stdin:
+        source = line.strip()
+        if sg.contains(source):
+            s = sg.index(source)
+            for v in graph.adj[s]:
+                print("  ", sg.name(v), end='')
+        else:
+            print("input not contains source: ", source)

algs4/topological.py

@@ -0,0 +1,49 @@
+"""
+ *  Execution:    python topological.py filename.txt delimiter
+ *  Data files:   https://algs4.cs.princeton.edu/42digraph/jobs.txt
+ *
+ *  Compute topological ordering of a DAG or edge-weighted DAG.
+ *  Runs in O(E + V) time.
+ *
+ *  % python topological.py jobs.txt "/"
+ *  Calculus
+ *  Linear Algebra
+ *  Introduction to CS
+ *  Advanced Programming
+ *  Algorithms
+ *  Theoretical CS
+ *  Artificial Intelligence
+ *  Robotics
+ *  Machine Learning
+ *  Neural Networks
+ *  Databases
+ *  Scientific Computing
+ *  Computational Biology
+ *
+"""
+
+from algs4.depth_first_order import DepthFirstOrder
+from algs4.directed_cycle import DirectedCycle
+from algs4.symbol_digraph import SymbolDigraph
+
+
+class Topological:
+    def __init__(self, g):
+        self.order = None
+        finder = DirectedCycle(g)
+        if not finder.has_cycle():
+            dfs = DepthFirstOrder(g)
+            self.order = dfs.reversePost()
+
+    def has_order(self):
+        return self.order != None
+
+
+if __name__ == "__main__":
+    import sys
+    filename = sys.argv[1]
+    delimiter = sys.argv[2]
+    sg = SymbolDigraph(filename, delimiter)
+    topological = Topological(sg.digraph())
+    for v in topological.order:
+        print(sg.name(v))