[leetcode]Binary Tree Level Order Traversal II

#include <iostream>
#include <vector>
#include <stack>
#include <queue>
using namespace std;

struct TreeNode {
int val;
TreeNode *left;
TreeNode *right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
public:
vector<vector<int> > levelOrderBottom(TreeNode *root) {
result.clear();
if (!root)
return result;

queue<TreeNode *> q;
q.push(root);

queue<TreeNode *> tmpQ;
while(!q.empty()){
while(!q.empty()){
tmpQ.push(q.front());
q.pop();
}

vector<int> oneLevel;
while(!tmpQ.empty()){
oneLevel.push_back(tmpQ.front()->val);
if (tmpQ.front()->left)
q.push(tmpQ.front()->left);
if (tmpQ.front()->right)
q.push(tmpQ.front()->right);
tmpQ.pop();
}

result.insert(result.begin(), oneLevel);//对于每一层，既然想从右到左遍历，那么就改变一下顺序就好了
//result.push_back(oneLevel);
}

return result;
}
private:
vector<vector<int> > result;
};

int main()
{

return 0;
}