二叉查找树中搜索区间

最新推荐文章于 2024-08-07 17:24:39 发布

zyaphone

最新推荐文章于 2024-08-07 17:24:39 发布

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分类专栏： lintcode python 文章标签： python

本文链接：https://blog.youkuaiyun.com/u012225151/article/details/51354477

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本文介绍了一种在二叉查找树中搜索指定区间内所有元素的方法，并提供了Python及Java实现代码。通过先序遍历的方式，递归地访问树中的节点，将值位于指定范围内的节点值收集起来，最后返回按升序排列的结果。

二叉查找树中搜索区间

Python

"""
Definition of TreeNode:
class TreeNode:
    def __init__(self, val):
        self.val = val
        self.left, self.right = None, None
"""
class Solution:
    """
    @param root: The root of the binary search tree.
    @param k1 and k2: range k1 to k2.
    @return: Return all keys that k1<=key<=k2 in ascending order.
    """     
    def searchRange(self, root, k1, k2):
        # write your code here
        L = []
        self.preOrderVisit(root, k1, k2, L)
        L = sorted(L)
        return L

    def preOrderVisit(self, root, k1, k2, L):
        if root == None:
            return
        else:
            if root.val >= k1 and root.val <= k2:
                L.append(root.val)
            self.preOrderVisit(root.left, k1, k2, L)
            self.preOrderVisit(root.right, k1, k2, L)

java

/**
 * Definition of TreeNode:
 * public class TreeNode {
 *     public int val;
 *     public TreeNode left, right;
 *     public TreeNode(int val) {
 *         this.val = val;
 *         this.left = this.right = null;
 *     }
 * }
 */
public class Solution {
    /**
     * @param root: The root of the binary search tree.
     * @param k1 and k2: range k1 to k2.
     * @return: Return all keys that k1<=key<=k2 in ascending order.
     */

    public ArrayList<Integer> searchRange(TreeNode root, int k1, int k2) {
        // write your code here
        ArrayList<Integer> L = new ArrayList();
        preOrderVisit(root, L, k1, k2);
        Collections.sort(L);
        return L;
    }

    private static void preOrderVisit(TreeNode root, ArrayList<Integer> L, int k1, int k2){
        if(root == null){
            return;
        }
        else{
            if(root.val >= k1 && root.val <=k2){
                L.add(root.val);
            }
            preOrderVisit(root.left, L, k1, k2);
            preOrderVisit(root.right, L, k1, k2);

        }

    }
}