77 lines
2.2 KiB
C++
77 lines
2.2 KiB
C++
// Source : https://leetcode.com/problems/binary-tree-right-side-view/
|
|
// Author : Hao Chen
|
|
// Date : 2015-04-07
|
|
|
|
/**********************************************************************************
|
|
*
|
|
* 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].
|
|
*
|
|
* Credits:Special thanks to @amrsaqr for adding this problem and creating all test cases.
|
|
*
|
|
**********************************************************************************/
|
|
|
|
/**
|
|
* Definition for binary tree
|
|
* struct TreeNode {
|
|
* int val;
|
|
* TreeNode *left;
|
|
* TreeNode *right;
|
|
* TreeNode(int x) : val(x), left(NULL), right(NULL) {}
|
|
* };
|
|
*/
|
|
class Solution {
|
|
public:
|
|
void rightSideViewHelper(TreeNode* root, int level, vector<int>& result) {
|
|
if (root == NULL) return;
|
|
if ( result.size() < level ) result.push_back(root->val);
|
|
rightSideViewHelper(root->right, level+1, result);
|
|
rightSideViewHelper(root->left, level+1, result);
|
|
}
|
|
|
|
void rightSideViewHelper(TreeNode* root, vector<int>& result) {
|
|
if (root==NULL) return;
|
|
|
|
vector<TreeNode*> stack;
|
|
vector<int> level;
|
|
stack.push_back(root);
|
|
level.push_back(1);
|
|
|
|
while (stack.size()>0) {
|
|
TreeNode* r = stack.back(); stack.pop_back();
|
|
int l = level.back(); level.pop_back();
|
|
if ( result.size() < l ) {
|
|
result.push_back(r->val);
|
|
}
|
|
if (r->left) {
|
|
stack.push_back(r->left);
|
|
level.push_back(l+1);
|
|
}
|
|
if (r->right) {
|
|
stack.push_back(r->right);
|
|
level.push_back(l+1);
|
|
}
|
|
}
|
|
}
|
|
vector<int> rightSideView(TreeNode *root) {
|
|
vector<int> result;
|
|
if (rand()%2){
|
|
rightSideViewHelper(root, 1, result);
|
|
}else{
|
|
rightSideViewHelper(root, result);
|
|
}
|
|
return result;
|
|
}
|
|
};
|