题解 | #二叉搜索树最小差值#

 * struct TreeNode {
 *	int val;
 *	struct TreeNode *left;
 *	struct TreeNode *right;
 *	TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
 * };
 */
class Solution {
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) {
        // write code here
        vector<int> res;
        solve(root, res);
        sort(res.begin(), res.end());
        int ans = INT_MAX, n = res.size();
        
        for (int i=1; i<n; ++i) {
            ans = min(ans, res[i] - res[i-1]);
        }
        
        return ans;
    }
    
private:
    void solve(TreeNode* root, vector<int>& res) {
        if (!root) {
            return;
        }
        res.push_back(root->val);
        solve(root->left, res);
        solve(root->right, res);
    }
};