Update 0108.将有序数组转换为二叉搜索树.md

更新java的 递归和迭代
This commit is contained in:
daniel1n
2021-07-02 15:41:43 +08:00
committed by GitHub
parent c41cb46ce0
commit 4d64b1fe75

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@ -209,6 +209,8 @@ public:
Java
递归: 左闭右开 [left,right)
```Java
class Solution {
public TreeNode sortedArrayToBST(int[] nums) {
@ -232,6 +234,75 @@ class Solution {
```
递归: 左闭右闭 [left,right]
```java
class Solution {
public TreeNode sortedArrayToBST(int[] nums) {
TreeNode root = traversal(nums, 0, nums.length - 1);
return root;
}
// 左闭右闭区间[left, right)
private TreeNode traversal(int[] nums, int left, int right) {
if (left > right) return null;
int mid = left + ((right - left) >> 1);
TreeNode root = new TreeNode(nums[mid]);
root.left = traversal(nums, left, mid - 1);
root.right = traversal(nums, mid + 1, right);
return root;
}
}
```
迭代: 左闭右闭 [left,right]
```java
class Solution {
public TreeNode sortedArrayToBST(int[] nums) {
if (nums.length == 0) return null;
//根节点初始化
TreeNode root = new TreeNode(-1);
Queue<TreeNode> nodeQueue = new LinkedList<>();
Queue<Integer> leftQueue = new LinkedList<>();
Queue<Integer> rightQueue = new LinkedList<>();
// 根节点入队列
nodeQueue.offer(root);
// 0为左区间下表初始位置
leftQueue.offer(0);
// nums.size() - 1为右区间下表初始位置
rightQueue.offer(nums.length - 1);
while (!nodeQueue.isEmpty()) {
TreeNode currNode = nodeQueue.poll();
int left = leftQueue.poll();
int right = rightQueue.poll();
int mid = left + ((right - left) >> 1);
// 将mid对应的元素给中间节点
currNode.val = nums[mid];
// 处理左区间
if (left <= mid - 1) {
currNode.left = new TreeNode(-1);
nodeQueue.offer(currNode.left);
leftQueue.offer(left);
rightQueue.offer(mid - 1);
}
// 处理右区间
if (right >= mid + 1) {
currNode.right = new TreeNode(-1);
nodeQueue.offer(currNode.right);
leftQueue.offer(mid + 1);
rightQueue.offer(right);
}
}
return root;
}
}
```
Python
```python3
# Definition for a binary tree node.