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[LeetCode] Binary Tree Right Side View

栏目:php教程时间:2015-06-05 09:07:29

Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom.

For example:
Given the following binary tree,

1 <--- / 2 3 <--- 5 4 <---

You should return [1, 3, 4].

解题思路

层次遍历法,找出每层最右真个结点。

实现代码1

/** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ // Runtime:7ms class Solution { public: vector<int> rightSideView(TreeNode *root) { vector<int> nums; queue<TreeNode*> nodes; if (root != NULL) { nodes.push(root); } TreeNode *cur; while (!nodes.empty()) { int size = nodes.size(); for (int i = 0; i < size; i++) { cur = nodes.front(); nodes.pop(); if (cur->left != NULL) { nodes.push(cur->left); } if (cur->right != NULL) { nodes.push(cur->right); } } nums.push_back(cur->val); } return nums; } };

实现代码2

# Definition for a binary tree node # class TreeNode: # def __init__(self, x): # self.val = x # self.left = None # self.right = None # Runtime:74ms class Solution: # @param root, a tree node # @return a list of integers def rightSideView(self, root): nums = [] if root == None: return nums nodes = [root] while nodes: size = len(nodes) for i in range(size): cur = nodes.pop(0) if cur.left != None: nodes.append(cur.left) if cur.right != None: nodes.append(cur.right) nums.append(cur.val) return nums;
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