Given a binary tree, return the level order traversal of its nodes’ values. (ie, from left to right, level by level).
For example:
Given binary tree [3,9,20,null,null,15,7],
return its level order traversal as:
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[
[3],
[9,20],
[15,7]
]
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class Solution {
public:
void (TreeNode *node,int high,vector<vector<int>> &vec) {
if (node == NULL)
return;
if (high + 1 > vec.size())
vec.resize(high + 1);
vec[high].push_back(node->val);
dfs(node->left,high + 1,vec);
dfs(node->right,high + 1,vec);
}
vector<vector<int>> levelOrder(TreeNode* root) {
vector<vector<int>> vec;
dfs(root,0,vec);
return vec;
}
};
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