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fix dart code for binary_search_tree (#711)

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liuyuxin 2023-08-31 16:55:16 +08:00 committed by GitHub
parent 95bc0ffdb2
commit 233e842d63
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1 changed files with 9 additions and 19 deletions
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28
codes/dart/chapter_tree/binary_search_tree.dart
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@ -12,9 +12,9 @@ class BinarySearchTree {
late TreeNode? _root; late TreeNode? _root;
/* 构造方法 */ /* 构造方法 */
BinarySearchTree(List<int> nums) { BinarySearchTree() {
nums.sort(); // 排序数组 // 初始化空树
_root = buildTree(nums, 0, nums.length - 1); // 构建二叉搜索树 _root = null;
} }
/* 获取二叉树的根节点 */ /* 获取二叉树的根节点 */
@ -22,19 +22,6 @@ class BinarySearchTree {
return _root; return _root;
} }
/* 构建二叉上搜索树 */
TreeNode? buildTree(List<int> nums, int i, int j) {
if (i > j) {
return null;
}
// 将数组中间节点作为根节点
int mid = (i + j) ~/ 2;
TreeNode? root = TreeNode(nums[mid]);
root.left = buildTree(nums, i, mid - 1);
root.right = buildTree(nums, mid + 1, j);
return root;
}
/* 查找节点 */ /* 查找节点 */
TreeNode? search(int num) { TreeNode? search(int num) {
TreeNode? cur = _root; TreeNode? cur = _root;
@ -87,7 +74,6 @@ class BinarySearchTree {
void remove(int num) { void remove(int num) {
// 若树为空，直接提前返回 // 若树为空，直接提前返回
if (_root == null) return; if (_root == null) return;
TreeNode? cur = _root; TreeNode? cur = _root;
TreeNode? pre = null; TreeNode? pre = null;
// 循环查找，越过叶节点后跳出 // 循环查找，越过叶节点后跳出
@ -136,8 +122,12 @@ class BinarySearchTree {
/* Driver Code */ /* Driver Code */
void main() { void main() {
/* 初始化二叉搜索树 */ /* 初始化二叉搜索树 */
List<int> nums = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]; BinarySearchTree bst = BinarySearchTree();
BinarySearchTree bst = BinarySearchTree(nums); // 请注意，不同的插入顺序会生成不同的二叉树，该序列可以生成一个完美二叉树
List<int> nums = [8, 4, 12, 2, 6, 10, 14, 1, 3, 5, 7, 9, 11, 13, 15];
for (int num in nums) {
bst.insert(num);
}
print("\n初始化的二叉树为\n"); print("\n初始化的二叉树为\n");
printTree(bst.getRoot()); printTree(bst.getRoot());