Leetcode 285. Inorder Successor in BST (Medium) (cpp)

Leetcode 285. Inorder Successor in BST (Medium) (cpp)

Tag: Tree

Difficulty: Medium

/*285. Inorder Successor in BST (Medium)Given a binary search tree and a node in it, find the in-order successor of that node in the BST.Note: If the given node has no in-order successor in the tree, return null.*//*** 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:TreeNode* inorderSuccessor(TreeNode* root, TreeNode* p) {stack<TreeNode*> s;iniSucSta(root, p, s);if (!s.empty() && s.top() == p) {getNextSuccessor(s);}return getNextSuccessor(s);}private:void iniSucSta(TreeNode* root, TreeNode* p, stack<TreeNode*>& s) {while (root != NULL) {if (root->val > p->val) {s.push(root);root = root->left;}else if (root->val < p->val) {root = root->right;}else {s.push(root);break;}}}TreeNode* getNextSuccessor(stack<TreeNode*>& s) {if (s.empty()) {return NULL;}TreeNode* cur = s.top();s.pop();TreeNode* temp = cur;cur = cur->right;while (cur != NULL) {s.push(cur);cur = cur->left;}return temp;}};