You need to find the largest value in each row of a binary tree.
Example:
Input: 1 / / 3 2 / / / 5 3 9 Output: [1, 3, 9]思路：dfs遍歷，然后順便記錄每層的最大值
/** * 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> ans; int maxLevel = 0; void dfs(TreeNode* root, int level){ if(root == NULL) return ; else { if(level > maxLevel){ ans.push_back(root->val); maxLevel = level; } else { if(root->val > ans[level - 1]) ans[level - 1] = root->val; } dfs(root->left, level + 1); dfs(root->right, level + 1); } } vector<int> largestValues(TreeNode* root) { dfs(root, 1); return ans; }};新聞熱點
疑難解答
