题解 | #求二叉树的层序遍历#
求二叉树的层序遍历
http://www.nowcoder.com/practice/04a5560e43e24e9db4595865dc9c63a3
class Solution {
public:
/**
*
* @param root TreeNode类
* @return int整型vector<vector<>>
*/
vector<vector<int> > levelOrder(TreeNode* root) {
queue<TreeNode* > q;
vector<vector<int> > result;
if(root)
q.push(root);
while(!q.empty())
{
int n=q.size();
vector<int> v;
while(n--)
{
TreeNode* p=q.front();
q.pop();
v.push_back(p->val);
if(p->left)
q.push(p->left);
if(p->right)
q.push(p->right);
}
result.push_back(v);
}
return result;
}
};注意考虑空树，
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