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Fix the return type of binary search tree and avl tree

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krahets
2023-04-14 05:47:20 +08:00
parent 9c9c8b7574
commit f7ae9c8a02
24 changed files with 247 additions and 451 deletions
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25
codes/zig/chapter_tree/avl_tree.zig
View File

@@ -108,9 +108,8 @@ pub fn AVLTree(comptime T: type) type {
}
// 插入节点
fn insert(self: *Self, val: T) !?*inc.TreeNode(T) {
fn insert(self: *Self, val: T) void {
self.root = try self.insertHelper(self.root, val);
return self.root;
}
// 递归插入节点（辅助方法）
@@ -137,9 +136,8 @@ pub fn AVLTree(comptime T: type) type {
}
// 删除节点
fn remove(self: *Self, val: T) ?*inc.TreeNode(T) {
fn remove(self: *Self, val: T) void {
self.root = self.removeHelper(self.root, val);
return self.root;
}
// 递归删除节点（辅助方法）
@@ -163,30 +161,21 @@ pub fn AVLTree(comptime T: type) type {
}
} else {
// 子节点数量 = 2 ，则将中序遍历的下个节点删除，并用该节点替换当前节点
var temp = self.getInOrderNext(node.?.right);
var temp = node.?.right;
while (temp.?.left != null) {
temp = temp.?.left;
}
node.?.right = self.removeHelper(node.?.right, temp.?.val);
node.?.val = temp.?.val;
}
}
self.updateHeight(node); // 更新节点高度
self.updateHeight(node); // 更新节点高度
// 2. 执行旋转操作，使该子树重新恢复平衡
node = self.rotate(node);
// 返回子树的根节点
return node;
}
// 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况）
fn getInOrderNext(self: *Self, node_: ?*inc.TreeNode(T)) ?*inc.TreeNode(T) {
_ = self;
var node = node_;
if (node == null) return node;
// 循环访问左子节点，直到叶节点时为最小节点，跳出
while (node.?.left != null) {
node = node.?.left;
}
return node;
}
// 查找节点
fn search(self: *Self, val: T) ?*inc.TreeNode(T) {
var cur = self.root;

41
codes/zig/chapter_tree/binary_search_tree.zig
View File

@@ -69,15 +69,15 @@ pub fn BinarySearchTree(comptime T: type) type {
}
// 插入节点
fn insert(self: *Self, num: T) !?*inc.TreeNode(T) {
fn insert(self: *Self, num: T) !void {
// 若树为空，直接提前返回
if (self.root == null) return null;
if (self.root == null) return;
var cur = self.root;
var pre: ?*inc.TreeNode(T) = null;
// 循环查找，越过叶节点后跳出
while (cur != null) {
// 找到重复节点，直接返回
if (cur.?.val == num) return null;
if (cur.?.val == num) return;
pre = cur;
// 插入位置在 cur 的右子树中
if (cur.?.val < num) {
@@ -95,13 +95,12 @@ pub fn BinarySearchTree(comptime T: type) type {
} else {
pre.?.left = node;
}
return node;
}
// 删除节点
fn remove(self: *Self, num: T) ?*inc.TreeNode(T) {
fn remove(self: *Self, num: T) !void {
// 若树为空，直接提前返回
if (self.root == null) return null;
if (self.root == null) return;
var cur = self.root;
var pre: ?*inc.TreeNode(T) = null;
// 循环查找，越过叶节点后跳出
@@ -118,7 +117,7 @@ pub fn BinarySearchTree(comptime T: type) type {
}
}
// 若无待删除节点，则直接返回
if (cur == null) return null;
if (cur == null) return;
// 子节点数量 = 0 or 1
if (cur.?.left == null or cur.?.right == null) {
// 当子节点数量 = 0 / 1 时， child = null / 该子节点
@@ -132,26 +131,16 @@ pub fn BinarySearchTree(comptime T: type) type {
// 子节点数量 = 2
} else {
// 获取中序遍历中 cur 的下一个节点
var nex = self.getInOrderNext(cur.?.right);
var tmp = nex.?.val;
// 递归删除节点 nex
_ = self.remove(nex.?.val);
// 将 nex 的值复制给 cur
cur.?.val = tmp;
var tmp = cur.?.right;
while (tmp.?.left != null) {
tmp = tmp.?.left;
}
var tmpVal = tmp.?.val;
// 递归删除节点 tmp
_ = self.remove(tmp.?.val);
// 用 tmp 覆盖 cur
cur.?.val = tmpVal;
}
return cur;
}
// 获取中序遍历中的下一个节点（仅适用于 root 有左子节点的情况）
fn getInOrderNext(self: *Self, node: ?*inc.TreeNode(T)) ?*inc.TreeNode(T) {
_ = self;
var node_tmp = node;
if (node_tmp == null) return null;
// 循环访问左子节点，直到叶节点时为最小节点，跳出
while (node_tmp.?.left != null) {
node_tmp = node_tmp.?.left;
}
return node_tmp;
}
};
}