add symbol graph

README.md

@@ -58,6 +58,7 @@ Try to keep the interface and variable name consistent with the original book wh
   * [BreadthFirstPaths](algs4/breadth_first_paths.py)
   * [CC](algs4/cc.py)
   * [Cycle](algs4/cycle.py)
+  * [SymbolGraph](algs4/symbol_graph.py)
 
 * 5 STRING
 

algs4/cc.py

@@ -0,0 +1,78 @@
+"""
+  Execution:    python cc.py filename.txt
+  Data files:   https://algs4.cs.princeton.edu/41graph/tinyG.txt
+                https://algs4.cs.princeton.edu/41graph/mediumG.txt
+                https://algs4.cs.princeton.edu/41graph/largeG.txt
+
+  Compute connected components using depth first search.
+  Runs in O(E + V) time.
+
+  % python cc.py tinyG.txt
+  3 components
+  0 1 2 3 4 5 6
+  7 8
+  9 10 11 12
+
+  % pytyon cc.py mediumG.txt
+  1 components
+  0 1 2 3 4 5 6 7 8 9 10 ...
+
+  % python cc.py largeG.txt
+  1 components
+  0 1 2 3 4 5 6 7 8 9 10 ...
+
+  Note: This implementation uses a recursive DFS. To avoid needing
+        a potentially very large stack size, replace with a non-recurisve
+        DFS ala NonrecursiveDFS.java.
+
+"""
+
+from algs4.bag import Bag
+from algs4.graph import Graph
+
+
+class CC:
+
+    def __init__(self, G):
+        self.marked = [False for _ in range(G.V)]
+        self.id = [0 for _ in range(G.V)]
+        self.count = 0
+
+        for s in range(G.V):
+            if not self.marked[s]:
+                self.dfs(G, s)
+                self.count += 1
+
+    def dfs(self, G, v):
+        self.marked[v] = True
+        self.id[v] = self.count
+        for w in G.adj[v]:
+            if not self.marked[w]:
+                self.dfs(G, w)
+
+    def connected(self, v, w):
+        return self.id[v] == self.id[w]
+
+if __name__ == "__main__":
+    import sys
+    f = open(sys.argv[1])
+    s = int(sys.argv[2])
+    V = int(f.readline())
+    E = int(f.readline())
+    g = Graph(V)
+    for i in range(E):
+        v, w = f.readline().split()
+        g.add_edge(v, w)
+    cc = CC(g)
+    print(cc.count, " components")
+    components = []
+    for i in range(cc.count):
+        components.append(Bag())
+
+    for v in range(g.V):
+        components[cc.id[v]].add(v)
+
+    for i in range(cc.count):
+        for v in components[i]:
+            print(v, " ", end='')
+        print()

algs4/cycle.py

@@ -0,0 +1,55 @@
+"""
+   Compilation:  javac Cycle.java
+   Execution:    java  Cycle filename.txt
+   Dependencies: Graph.java Stack.java In.java StdOut.java
+   Data files:   https: // algs4.cs.princeton.edu / 41graph / tinyG.txt
+                 https: // algs4.cs.princeton.edu / 41graph / mediumG.txt
+                 https: // algs4.cs.princeton.edu / 41graph / largeG.txt
+ 
+   Identifies a cycle.
+   Runs in O(E + V) time.
+ 
+  % java Cycle tinyG.txt
+   3 4 5 3
+ 
+  % java Cycle mediumG.txt
+   15 0 225 15
+ 
+  % java Cycle largeG.txt
+   996673 762 840164 4619 785187 194717 996673
+ """
+
+from algs4.graph import Graph
+
+
+class Cycle:
+
+    def __init__(self, G):
+        self.marked = [False for _ in range(G.V)]
+        self.has_cycle = False
+        for s in range(G.V):
+            if not self.marked[s]:
+                self.dfs(G, s, s)
+
+    def dfs(self, G, v, u):
+        self.marked[v] = True
+        for w in G.adj[v]:
+            if not self.marked[w]:
+                self.dfs(G, w, v)
+            elif w != u:
+                self.has_cycle = True
+
+if __name__ == "__main__":
+    import sys
+    f = open(sys.argv[1])
+    V = int(f.readline())
+    E = int(f.readline())
+    g = Graph(V)
+    for i in range(E):
+        v, w = f.readline().split()
+        g.add_edge(v, w)
+    cycle = Cycle(g)
+    if cycle.has_cycle:
+        print("Graph is cyclic")
+    else:
+        print("Graph is acyclic")

algs4/st.py

@@ -1,30 +1,52 @@
 """
-  Execution:    python st < input.txt
+  Execution:    python st.py < input.txt
   Data files:   https://algs4.cs.princeton.edu/35applications/tinyST.txt
   
+  Sorted symbol table implementation using a python collections.OrderedDict
   Does not allow duplicates.
  """
 
+from collections import OrderedDict
+
 
 class ST:
 
+    def __init__(self):
+        self.st = OrderedDict()
+
     def put(self, key, value):
-        pass
+        self.st[key] = value
 
     def get(self, key):
-        pass
+        if key is None:
+            raise ValueError("calls get() with null key")
+
+        return self.st.get(key)
 
     def delete(self, key):
-        pass
+        if key is None:
+            raise ValueError("calls get() with null key")
+        del self.st[key]
 
     def contains(self, key):
-        pass
+        return key in self.st
 
     def is_empty(self):
-        pass
+        self.size() == 0
 
     def size(self):
-        pass
+        return len(self.st.keys())
 
     def keys(self):
-        pass
+        return self.st.keys()
+
+if __name__ == "__main__":
+    import sys
+    st = ST()
+    i = 0
+    for line in sys.stdin:
+        st.put(line, i)
+        i += 1
+
+    for key in st.keys():
+        print("%s : %s " % (key, st.get(key)))

algs4/symbol_graph.py

@@ -0,0 +1,93 @@
+"""
+   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.graph import Graph
+
+
+class SymbolGraph:
+
+    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 = Graph(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 graph(self):
+        return self.G
+
+if __name__ == "__main__":
+    import sys
+    filename, delimiter = sys.argv[1], sys.argv[2]
+    sg = SymbolGraph(filename, delimiter)
+    graph = sg.graph()
+
+    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)