This commit is contained in:
krahets
2024-04-11 01:11:20 +08:00
parent a6adc8e20a
commit 739f8a31bb
85 changed files with 1555 additions and 979 deletions
+29 -19
View File
@@ -448,7 +448,7 @@ AVL 樹既是二元搜尋樹,也是平衡二元樹,同時滿足這兩類二
/* 更新節點高度 */
fun updateHeight(node: TreeNode?) {
// 節點高度等於最高子樹高度 + 1
node?.height = (max(height(node?.left).toDouble(), height(node?.right).toDouble()) + 1).toInt()
node?.height = max(height(node?.left), height(node?.right)) + 1
}
```
@@ -2012,20 +2012,22 @@ AVL 樹的節點插入操作與二元搜尋樹在主體上類似。唯一的區
```kotlin title="avl_tree.kt"
/* 插入節點 */
fun insert(value: Int) {
root = insertHelper(root, value)
fun insert(_val: Int) {
root = insertHelper(root, _val)
}
/* 遞迴插入節點(輔助方法) */
fun insertHelper(n: TreeNode?, value: Int): TreeNode {
fun insertHelper(n: TreeNode?, _val: Int): TreeNode {
if (n == null)
return TreeNode(value)
return TreeNode(_val)
var node = n
/* 1. 查詢插入位置並插入節點 */
if (value < node.value) node.left = insertHelper(node.left, value)
else if (value > node.value) node.right = insertHelper(node.right, value)
else return node // 重複節點不插入,直接返回
if (_val < node._val)
node.left = insertHelper(node.left, _val)
else if (_val > node._val)
node.right = insertHelper(node.right, _val)
else
return node // 重複節點不插入,直接返回
updateHeight(node) // 更新節點高度
/* 2. 執行旋轉操作,使該子樹重新恢復平衡 */
node = rotate(node)
@@ -2593,30 +2595,38 @@ AVL 樹的節點插入操作與二元搜尋樹在主體上類似。唯一的區
```kotlin title="avl_tree.kt"
/* 刪除節點 */
fun remove(value: Int) {
root = removeHelper(root, value)
fun remove(_val: Int) {
root = removeHelper(root, _val)
}
/* 遞迴刪除節點(輔助方法) */
fun removeHelper(n: TreeNode?, value: Int): TreeNode? {
fun removeHelper(n: TreeNode?, _val: Int): TreeNode? {
var node = n ?: return null
/* 1. 查詢節點並刪除 */
if (value < node.value) node.left = removeHelper(node.left, value)
else if (value > node.value) node.right = removeHelper(node.right, value)
if (_val < node._val)
node.left = removeHelper(node.left, _val)
else if (_val > node._val)
node.right = removeHelper(node.right, _val)
else {
if (node.left == null || node.right == null) {
val child = if (node.left != null) node.left else node.right
val child = if (node.left != null)
node.left
else
node.right
// 子節點數量 = 0 ,直接刪除 node 並返回
if (child == null) return null
else node = child
if (child == null)
return null
// 子節點數量 = 1 ,直接刪除 node
else
node = child
} else {
// 子節點數量 = 2 ,則將中序走訪的下個節點刪除,並用該節點替換當前節點
var temp = node.right
while (temp!!.left != null) {
temp = temp.left
}
node.right = removeHelper(node.right, temp.value)
node.value = temp.value
node.right = removeHelper(node.right, temp._val)
node._val = temp._val
}
}
updateHeight(node) // 更新節點高度