538. Convert BST to Greater Tree
阿新 • • 發佈:2018-01-11
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Given a Binary Search Tree (BST), convert it to a Greater Tree such that every key of the original BST is changed to the original key plus sum of all keys greater than the original key in BST.
Example:
Input: The root of a Binary Search Tree like this: 5 / 2 13 Output: The root of a Greater Tree like this: 18 / 20 13
大致意思是每個節點加上比這個節點大的所有值,生成一個新的數
中序遍歷即可
int sum = 0; public TreeNode convertBST(TreeNode root) { if(root!=null) { convertBST(root.right); sum+=root.val; root.val=sum; convertBST(root.left); } return root; }
538. Convert BST to Greater Tree