图的深度优先搜索

Author: 朱睿家

chapter-22/bfs.js

@@ -1,4 +1,4 @@
-// 有向无环图的广度遍历
+// 从某个点出发的广度遍历
 function bfs(G, s) {
     let SimulationTree = {};
     let didSearchMap = new Map();

chapter-22/dfs.js

@@ -1,42 +1,5 @@
-function Node(key) {
-    this.key = key || null
-    this.pre = null
-    this.next = null
-}
-
-let node1 = new Node(1)
-let node1_2 = new Node(2)
-let node1_2_4 = new Node(4)
-let node2 = new Node(2)
-let node2_5 = new Node(5)
-let node3 = new Node(3)
-let node3_6 = new Node(6)
-let node3_6_5 = new Node(5)
-let node4 = new Node(4)
-let node4_2 = new Node(2)
-let node5 = new Node(5)
-let node5_4 = new Node(4)
-let node6 = new Node(6)
-let node6_6 = new Node(6)
-node1.next = node1_2
-node1_2.pre = node1
-node1_2.next = node1_2_4
-node1_2_4.pre = node1_2
-node2.next = node2_5
-node2_5.pre = node2
-node3.next = node3_6
-node3_6.pre = node3
-node3_6.next = node3_6_5
-node3_6_5.pre = node3_6
-node4.next = node4_2
-node4_2.pre = node4
-node5.next = node5_4
-node5_4.pre = node5
-node6.next = node6_6
-node6_6.pre = node6
-
-const G = [node1, node2, node3, node4, node5, node6]
 
+// 从某个点出发的深度遍历
 function dfs(G, s) {
 
     function getStartNodeIndex(P, a) {
@@ -47,29 +10,56 @@ function dfs(G, s) {
     let SimulationTree = {};
     let didSearchMap = new Map();
 
-    function  search(startNode,SimulationTree){
+    function findNext(inputNode) {
+        let resultNode;
+        function nextEdgeNode(node) {
+            if (node.next === null) {
+                resultNode = null
+            } else if (didSearchMap[node.next.key] === 1) {
+                nextEdgeNode(node.next)
+            } else {
+                resultNode = node.next
+            }
+        }
+        nextEdgeNode(inputNode)
+        return resultNode
+    }
+
+    function search(startNode, SimulationTree) {
         let stack = [];
         function searchDeep(node, tree) {
-            tree[node.key] = new Object({})
-            stack.push(node.next);
-            didSearchMap[node.key] = 1
-            if (node.next !== null) {
+            tree[node.key] === undefined ? tree[node.key] = new Object({}) : null;
+            didSearchMap[node.key] = 1; //记录已经走过的节点
+            if (node.next === null) { //如果为空返回上一个节点
+                if (stack.length !== 0) {
+                    let preNode = stack.pop();
+                    let resultNode = findNext(preNode);
+                    if (resultNode) {
+                        let t = G[getStartNodeIndex(G, resultNode.key)]
+                        search(t, tree);
+                    }
+                }
+            } else {
                 let nextNode = G[getStartNodeIndex(G, node.next.key)]
                 if (!didSearchMap[nextNode.key]) {
-                    searchDeep(nextNode, tree[node.key])
-                }else{
-                    stack.pop();
-                    search(node,)
+                    stack.push(node); //保存上一个节点
+                    searchDeep(nextNode, tree[node.key]);
+                } else { // 遇到已经经过的节点 返回上一个节点 查找是否有其他路径
+                    if (stack.length !== 0) {
+                        let preNode = stack.pop(); // 找回上一个节点
+                        let resultNode = findNext(preNode); // 去邻接链表中查询对应没有经过的节点
+                        if (resultNode) {
+                            let t = G[getStartNodeIndex(G, resultNode.key)]
+                            search(t, tree);
+                        }
+                    }
                 }
-            }else{
-
             }
         }
         searchDeep(startNode, SimulationTree);
     }
-    search(startNode,SimulationTree)
+    search(startNode, SimulationTree)
     return SimulationTree
 }
 
-// dfs(G, 1)
-console.log(JSON.stringify(dfs(G, 1)))
+module.exports = dfs;

test/dfs.test.js

@@ -0,0 +1,44 @@
+function Node(key) {
+    this.key = key || null
+    this.pre = null
+    this.next = null
+}
+
+let node1 = new Node(1)
+let node1_2 = new Node(2)
+let node1_2_4 = new Node(4)
+let node2 = new Node(2)
+let node2_5 = new Node(5)
+let node3 = new Node(3)
+let node3_6 = new Node(6)
+let node3_6_5 = new Node(5)
+let node4 = new Node(4)
+let node4_2 = new Node(2)
+let node5 = new Node(5)
+let node5_4 = new Node(4)
+let node6 = new Node(6)
+let node6_6 = new Node(6)
+node1.next = node1_2
+node1_2.pre = node1
+node1_2.next = node1_2_4
+node1_2_4.pre = node1_2
+node2.next = node2_5
+node2_5.pre = node2
+node3.next = node3_6
+node3_6.pre = node3
+node3_6.next = node3_6_5
+node3_6_5.pre = node3_6
+node4.next = node4_2
+node4_2.pre = node4
+node5.next = node5_4
+node5_4.pre = node5
+node6.next = node6_6
+node6_6.pre = node6
+
+const G = [node1, node2, node3, node4, node5, node6]
+
+const dfs = require('../chapter-22/dfs');
+
+test('邻接链矩阵的深度搜索',()=>{
+    expect(dfs(G,3)).toEqual({"3":{"6":{},"5":{"4":{"2":{}}}}})
+})