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leetcode刷题.530. 二叉搜索树的最小绝对差.每日打卡

程序员文章站 2022-04-24 16:28:48
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leetcode刷题.530. 二叉搜索树的最小绝对差.每日打卡

class Solution {
public:

    int threeMin(int a, int b, int c) {
        return (a > b) ? ((b > c) ? c : b) : ((a > c) ? c : a);
    }
    int maxTreeNode(TreeNode *root) {

        while(nullptr != root->right)
            root = root->right;
        return root->val;
    }

    int minTreeNode(TreeNode *root) {

        while(nullptr != root->left) 
            root = root->left;
        return root->val;
    }
    
    int getMinimumDifference(TreeNode* root) {

        int min_av = INT_MAX;
        stack<TreeNode *> mystack;
        mystack.push(root);

        while(mystack.size()) {

            TreeNode *node = mystack.top();
            mystack.pop();
            int r = INT_MAX, l = INT_MAX;

            if(nullptr != node->right) {
                mystack.push(node->right);
                r = abs(minTreeNode(node->right) - node->val);
            }
            if(nullptr != node->left) {
                mystack.push(node->left);
                l = abs(maxTreeNode(node->left) - node->val);
            }
            min_av = threeMin(min_av, r, l);
        } 
        return min_av;
    }
};