标签：point number get bst target poi public struct col
Given a Binary Search Tree and a target number, return true if there exist two elements in the BST such that their sum is equal to the given target.
Example 1:
Input:
5
/ 3 6
/ \ 2 4 7
Target = 9
Output: True
Example 2:
Input:
5
/ 3 6
/ \ 2 4 7
Target = 28
Output: False
给定一个二叉树，对其求树中两个元素的和是否满足给定值。
1. 对二叉树进行中序遍历并把结果放入一个数组中
2. 对数组进行Two Pointer查找即可。
/** * 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: vector<int> inOrder; bool findTarget(TreeNode* root, int k) { if (root == nullptr) return false; inOrdertoVec(root); if (inOrder.size() == 1) return false; int left = 0, right = inOrder.size() - 1; while (left < right) { int sum = inOrder[left] + inOrder[right]; if (sum == k) return true; else if (sum < k) left++; else right--; } return false; } vector<int> inOrdertoVec(TreeNode* root) { if (root == nullptr) return inOrder; stack<TreeNode*> s; while (root || !s.empty()) { if (root != nullptr) { s.push(root); root = root->left; } else { root = s.top(); inOrder.push_back(root->val); s.pop(); root = root->right; } } return inOrder; } }; // 35 ms
[LeetCode] Two Sum IV - Input is a BST
标签：point number get bst target poi public struct col
原文地址：http://www.cnblogs.com/immjc/p/7500427.html
