题解 | #二叉搜索树最小差值# | C++

/**
 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
#include <climits>
class Solution {
    void travelMidOrder(TreeNode* node, int& last_val, int& ans) {
        if (node == nullptr) return;
        travelMidOrder(node->left, last_val, ans);
        if (last_val != -1) {
            ans = std::min(ans, std::abs(node->val - last_val));
        }
        last_val = node->val;
        travelMidOrder(node->right, last_val, ans);
    }
public:
    /**
     * 代码中的类名、方法名、参数名已经指定，请勿修改，直接返回方法规定的值即可
     *
     * 
     * @param root TreeNode类 
     * @return int整型
     */
    int minDifference(TreeNode* root) {
        int ans = INT_MAX;
        int last_val = -1;
        travelMidOrder(root, last_val, ans);
        return ans;
    }
};