标签：values between and put logs java get des sea
Given a binary search tree with non-negative values, find the minimum absolute difference between values of any two nodes.
Example:
Input:
1
3
/
2
Output:
1
Explanation:
The minimum absolute difference is 1, which is the difference between 2 and 1 (or between 2 and 3).
Note: There are at least two nodes in this BST.
Approach #1: C++.
/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
* };
*/
class Solution {
public:
int getMinimumDifference(TreeNode* root) {
if (root->left != NULL)
getMinimumDifference(root->left);
if (pre != NULL) {
imin = min(imin, root->val - pre->val);
}
pre = root;
if (root->right != NULL)
getMinimumDifference(root->right);
return imin;
}
private:
int imin = INT_MAX;
TreeNode* pre = NULL;
};
Appraoch #2: Java.
public class Solution {
TreeSet<Integer> set = new TreeSet<>();
int min = Integer.MAX_VALUE;
public int getMinimumDifference(TreeNode root) {
if (root == null) return min;
if (!set.isEmpty()) {
if (set.floor(root.val) != null) {
min = Math.min(min, root.val - set.floor(root.val));
}
if (set.ceiling(root.val) != null) {
min = Math.min(min, set.ceiling(root.val) - root.val);
}
}
set.add(root.val);
getMinimumDifference(root.left);
getMinimumDifference(root.right);
return min;
}
}
At the first time, I want to use c++ to realise above code, I can use set upper_bound to replace set.ceiling but I can‘t find the suitable method to replace the set.floor.
there are some notes about java syntax:
1. The difference between int and Integer in java.
Approach #3: Python.
# Definition for a binary tree node.
# class TreeNode(object):
# def __init__(self, x):
# self.val = x
# self.left = None
# self.right = None
class Solution(object):
def getMinimumDifference(self, root):
"""
:type root: TreeNode
:rtype: int
"""
L = []
def dfs(root):
if root.left: dfs(root.left)
L.append(root.val)
if root.right: dfs(root.right)
dfs(root)
return min(abs(a-b) for a, b in zip(L, L[1:]))
There are some syntax in python:
530. Minimum Absolute Difference in BST
标签：values between and put logs java get des sea
原文地址：https://www.cnblogs.com/ruruozhenhao/p/10048687.html
