增加了二叉树的增删改

typescript/24_treesearch/TreeSearch.ts

@@ -0,0 +1,129 @@
+/**
+ * 二叉树的增删查操作
+ */
+export class TreeSearch {
+  private root?: Node
+
+  public find(data: number) {
+    let p = this.root
+    while (p != null) {
+      if (data < p.data) {
+        p = p.left
+      } else if (data > p.data) {
+        p = p.right
+      } else {
+        return p
+      }
+    }
+    return p
+  }
+
+  public insert(data: number) {
+    if (this.root == null) {
+      this.root = new Node(data)
+      return
+    }
+    let p = this.root
+    while (p != null) {
+      if (data < p.data) {
+        if (p.left == null) {
+          p.left = new Node(data)
+          return
+        } else {
+          p = p.left
+        }
+      } else {
+        if (data > p.data) {
+          if (p.right == null) {
+            p.right = new Node(data)
+            return
+          } else {
+            p = p.right
+          }
+        }
+      }
+    }
+  }
+
+  /**
+   * 删除的时候分三种情况
+   * @param data
+   */
+  public delete(data: number) {
+    // 先把对应的元素找出来,并且为了删除，也得记录父节点的内存地址
+    // 包含了null或者undefined两种情况
+    if (this.root == null) return
+    let p: Node | undefined = this.root
+    let pp = this.root
+    while (p != null && p.data !== data) {
+      pp = p
+      data > p.data ? p = p.right : p = p.left
+    }
+    // 没有找到要删除的元素
+    if (p == null) return
+    // 要删除的元素有两个子节点,需要找到右子树的最小节点，然后赋值
+    if (p.left != null && p.right != null) {
+      // 右子树的最小节点
+      let minP = p.right
+      // 右子树的最小节点的父节点
+      let minPP = p
+      while (minP.left != null) {
+        minPP = minP
+        minP = minP.left
+      }
+      p.data = minP.data
+      p = minP
+      pp = minPP
+    }
+
+    // 有一个子节点或者没有子节点
+    let child
+    if (p.left != null) {
+      child = p.left
+    } else if (p.right != null) {
+      child = p.right
+    } else {
+      child = null
+    }
+    if (pp == null) {
+      this.root = undefined
+    } else if (pp.left === p) {
+      pp.left = child!
+    } else {
+      pp.right = child!
+    }
+  }
+
+  public printAllData(): void {
+    this.printAll(this.root)
+  }
+
+  private printAll(node?: Node): void {
+    if (node == null) return
+    console.log(node.data)
+    this.printAll(node.left)
+    this.printAll(node.right)
+  }
+}
+
+export class Node {
+  data: number
+  left?: Node
+  right?: Node
+
+  constructor(data: number) {
+    this.data = data
+  }
+}
+
+const treeSearch = new TreeSearch()
+treeSearch.insert(1)
+treeSearch.insert(4)
+treeSearch.insert(3)
+treeSearch.insert(2)
+treeSearch.insert(5)
+treeSearch.insert(0)
+
+treeSearch.delete(4)
+
+treeSearch.printAllData()