Logic: reverse order of queue push and then reverse the vector before returning
vector Solution::solve(TreeNode* A) {
if(A==NULL) return {};queue<TreeNode*> q; vector<int>res; q.push(A); while(q.size()) { TreeNode* temp=q.front(); q.pop(); if(temp!=NULL) { res.push_back(temp->val); if(temp->right) q.push(temp->right); // push in reverse order if(temp->left) q.push(temp->left); } } reverse(res.begin(),res.end()); return res;}