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lc-lonelynodes.cpp
51 lines (42 loc) · 1.35 KB
/
lc-lonelynodes.cpp
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/**
* Definition for a binary tree node.
* struct TreeNode {
* int val;
* TreeNode *left;
* TreeNode *right;
* TreeNode() : val(0), left(nullptr), right(nullptr) {}
* TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
* TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
* };
*/
#include <queue>
class Solution {
public:
bool hasSingleChild(TreeNode * root);
TreeNode * getSingleChild(TreeNode * root);
vector<int> getLonelyNodes(TreeNode * root) {
vector<int> lonelynodes;
queue<TreeNode *> nodeQ;
nodeQ.push(root);
while (nodeQ.size()) {
TreeNode * current = nodeQ.front();
nodeQ.pop();
if (hasSingleChild(current)) {
lonelynodes.push_back(getSingleChild(current)->val);
}
if (current->left) {
nodeQ.push(current->left);
}
if (current->right) {
nodeQ.push(current->right);
}
};
return lonelynodes;
}
};
bool Solution::hasSingleChild(TreeNode *root) {
return (!root->left && root->right) || (root->left && !root->right);
};
TreeNode *Solution::getSingleChild(TreeNode *root) {
return root->left ? root->left : root->right;
};