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Diffstat (limited to 'other/convert_sorted_bst.cpp')
-rw-r--r-- | other/convert_sorted_bst.cpp | 29 |
1 files changed, 29 insertions, 0 deletions
diff --git a/other/convert_sorted_bst.cpp b/other/convert_sorted_bst.cpp new file mode 100644 index 0000000..8b5b656 --- /dev/null +++ b/other/convert_sorted_bst.cpp @@ -0,0 +1,29 @@ +// 109. Convert Sorted List to Binary Search Tree +#include "leetcode.h" + +/* + * given 'head' of a singly linked list where elements are sorted in ascending + * order convert it to a height balanced binary search tree. meaning the depth + * of two sub- trees of every node never differs by more than one. + */ + +class Solution { +public: + TreeNode *sortedListToBST(ListNode *head) { + if (!head) + return NULL; + if (!head->next) + return new TreeNode(head->val); + auto slow = head, fast = head, pre = head; + while (fast && fast->next) { + pre = slow; + slow = slow->next; + fast = fast->next->next; + } + pre->next = 0; + TreeNode *root = new TreeNode(slow->val); + root->left = sortedListToBST(head); + root->right = sortedListToBST(slow->next); + return root; + } +}; |