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Binary Tree Level Order Traversal

2015-04-11 11:06  笨笨的老兔子  阅读(138)  评论(0)    收藏  举报

从根节点开始按层次遍历一棵二叉树

思路：广搜即可

  1. class Solution {
  2. public:
  3.     vector<vector<int> > levelOrder(TreeNode *root) {
  4.         vector<vector<int> > resVec;
  5.         if (!root)
  6.             return resVec;
  7.         queue<TreeNode*> nodeQue;
  8.         nodeQue.push(root);
  10.         while (!nodeQue.empty())
  11.         {
  12.             vector<int> subVec;
  13.             int qSize = nodeQue.size();
  14.             for (size_t i = 0; i < qSize; i++)
  15.             {
  16.                 if (nodeQue.front()->left)
  17.                     nodeQue.push(nodeQue.front()->left);
  18.                 if (nodeQue.front()->right)
  19.                     nodeQue.push(nodeQue.front()->right);
  20.                 subVec.push_back(nodeQue.front()->val);
  21.                 nodeQue.pop();
  22.             }
  23.             resVec.push_back(subVec);
  24.         }
  25.         return resVec;
  26.     }
  27. };