C语言 | Leetcode C语言题解之第538题把二叉搜索树转换为累加树

题目：

题解：

struct TreeNode* getSuccessor(struct TreeNode* node) {struct TreeNode* succ = node->right;while (succ->left != NULL && succ->left != node) {succ = succ->left;}return succ;
}struct TreeNode* convertBST(struct TreeNode* root) {int sum = 0;struct TreeNode* node = root;while (node != NULL) {if (node->right == NULL) {sum += node->val;node->val = sum;node = node->left;} else {struct TreeNode* succ = getSuccessor(node);if (succ->left == NULL) {succ->left = node;node = node->right;} else {succ->left = NULL;sum += node->val;node->val = sum;node = node->left;}}}return root;
}