初步完成 邻接表-稀疏图

Author: Jiang Haifeng

GraphTheory/src/DenseGraph.java

@@ -53,7 +53,11 @@ public boolean hasEdge(int v, int w) {
         return g.get(v).get(w);
     }
 
+    public Iterable<Integer> pathTo(int v) {
+        return null;
+    }
 
+    // 暂废弃
     class adjIterator implements Iterator {
         private DenseGraph G;
         private int v;

GraphTheory/src/Main.java

@@ -1,4 +1,3 @@
-import java.util.Iterator;
 import java.util.Random;
 
 public class Main {
@@ -14,10 +13,15 @@ public static void main(String[] args) {
             int b = random.nextInt(N);
             sparseGraph.addEdge(a, b);
         }
+        System.out.println(sparseGraph);
 
         for (int v = 0; v < N; v++) {
-            System.out.println(v + " : ");
-            SparseGraph.AdjIterator iterator = new SparseGraph.AdjIterator(sparseGraph, v);
+            System.out.print(v + " : ");
+            SparseGraph.adjIterator iterator = sparseGraph.new adjIterator(sparseGraph, v);
+            while (iterator.hasNext()) {
+                System.out.print(iterator.next() + " ");
+            }
+            System.out.println();
         }
     }
 }

GraphTheory/src/SparseGraph.java

@@ -1,6 +1,7 @@
 import java.util.ArrayList;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Stack;
 
 // 稀疏图 - 邻接表
 public class SparseGraph {
@@ -57,20 +58,40 @@ public boolean hasEdge(int v, int w) {
         return false;
     }
 
-    public class AdjIterator implements Iterator {
+    @Override
+    public String toString() {
+        StringBuilder stringBuilder = new StringBuilder();
+        stringBuilder.append("SparseGraph\n");
+        stringBuilder.append("-----------\n");
+        for (int i = 0; i < g.size(); i++) {
+            List<Integer> line = g.get(i);
+            stringBuilder.append(i);
+            stringBuilder.append(" : ");
+            for (int j = 0; j < line.size(); j++) {
+                int v = line.get(j);
+                stringBuilder.append(v);
+                if (j < line.size() - 1)
+                    stringBuilder.append(", ");
+            }
+            stringBuilder.append("\n");
+        }
+        return stringBuilder.toString();
+    }
+
+    public class adjIterator implements Iterator {
         private SparseGraph G;
         private int v;
         int index;
 
-        public AdjIterator(SparseGraph graph, int v) {
+        public adjIterator(SparseGraph graph, int v) {
             this.G = graph;
             this.v = v;
-            this.index = 0;
+            this.index = -1;
         }
 
         @Override
         public boolean hasNext() {
-            return index >= G.g.get(v).size();
+            return index + 1 < G.g.get(v).size();
         }
 
         @Override

README.md

@@ -47,6 +47,9 @@
     * [红黑树_pending](./RedBlackTree/src/RBTree.java)
 - 【哈希表】
     - [HashTable](./HashTable/src/HashTable.java)
+- 【图论】
+    - [稠密图 - 邻接矩阵](./GraphTheory/src/DenseGraph.java)
+    - [稀疏图 - 邻接表](./GraphTheory/src/SparseGraph.java)
 
 
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