class Solution { public: vector<vector<int> > Print(TreeNode* pRoot) { vector<vector<int> > vec; if(pRoot == NULL) return vec; queue<TreeNode*> q; q.push(pRoot); while(!q.empty()) { int lo = 0, hi = q.size(); vector<int> c; while(lo++ < hi) { TreeNode *t = q.front(); q.pop(); c.push_back(t->val); if(t->left) q.push(t->left); if(t->right) q.push(t->right); } vec.push_back(c); } return vec; } };
熟练使用队列