按之字形顺序打印二叉树

/*
struct TreeNode {
int val;
struct TreeNode *left;
struct TreeNode *right;
TreeNode(int x) :
val(x), left(NULL), right(NULL) {
}
};
*/
class Solution {
public:
vector<vector<int>> ans;
void shoushu(TreeNode *pRoot,int p ){
if(pRoot==NULL) return ;
if(ans.size()==p)
ans.push_back(vector<int>());
ans[p].push_back(pRoot->val);
shoushu(pRoot->left,p+1);
shoushu(pRoot->right,p+1);

}
vector<vector<int> > Print(TreeNode* pRoot) {
shoushu(pRoot,0);
for(int i=0;i<ans.size();i++){
if(i&1){
reverse(ans[i].begin(),ans[i].end());
}
}
return ans;
}

};