LintCode题解之Search Range in Binary Search Tree

1、题目描述

2、问题分析

首先将二叉查找树使用中序遍历的方式将元素放入一个vector，然后在vector 中截取符合条件的数字。

3、代码

/**
 * Definition of TreeNode:
 * class TreeNode {
 * public:
 *     int val;
 *     TreeNode *left, *right;
 *     TreeNode(int val) {
 *         this->val = val;
 *         this->left = this->right = NULL;
 *     }
 * }
 */

class Solution {
public:
    /**
     * @param root: param root: The root of the binary search tree
     * @param k1: An integer
     * @param k2: An integer
     * @return: return: Return all keys that k1<=key<=k2 in ascending order
     */
    vector<int> searchRange(TreeNode * root, int k1, int k2) {
        // write your code here
        vector<int> num ;
        inorder(num, root);
        
        
        
        vector<int> res;
        if( num.size() == 0)
            return res;
        int i = 0;
        int j = num.size() - 1;
        while( num[i] < k1) i++;
        while( num[j] > k2) j--;
        
        for(int k=  i; k <= j; k++){
            res.push_back(num[k]);
        }
        
        return res;
        
    }
    
    void  inorder(vector<int>& nums , TreeNode *root){
        if( root != NULL ){
            inorder(nums, root->left);
            nums.push_back(root->val);
            inorder(nums,root->right);
        }else {
            return ;
        }
            
        
      
    }
    
};