class Solution {
public:
void doit(TreeNode* now,vector<int>& v){
if(now->left != NULL) doit(now->left,v);
v.push_back(now->val);
if(now->right != NULL) doit(now->right,v);
}
vector<int> getAllElements(TreeNode* root1, TreeNode* root2) {
vector<int> treeA;
vector<int> treeB;
if(root1 != NULL) doit(root1,treeA);
if(root2 != NULL) doit(root2,treeB);
vector<int> ans(treeA.size()+treeB.size(),0);
int a = 0;
int b = 0;
int loc = 0;
while(a<treeA.size() && b<treeB.size()){
if(treeA[a] <= treeB[b]) ans[loc++] = treeA[a++];
else ans[loc++] = treeB[b++];
}
while(a<treeA.size()) ans[loc++] = treeA[a++];
while(b<treeB.size()) ans[loc++] = treeB[b++];
return ans;
}
};