标签：des style blog color io strong for ar
Given a binary tree, return the preorder traversal of its nodes‘ values.
For example:
Given binary tree {1,#,2,3},
1
2
/
3
return [1,2,3].
Note: Recursive solution is trivial, could you do it iteratively?
思路：取栈顶元素，输出该元素并将其出栈；若其右子树不空，将右子节点入栈；若其左子树不空，将左子节点入栈。循环直到栈为空。
1 class Solution { 2 public: 3 vector<int> preorderTraversal( TreeNode *root ) { 4 vector<int> result; 5 if( !root ) { return result; } 6 stack<TreeNode*> nodesStack; 7 nodesStack.push( root ); 8 while( !nodesStack.empty() ) { 9 TreeNode* curr = nodesStack.top(); 10 nodesStack.pop(); 11 result.push_back( curr->val ); 12 if( curr->right ) { nodesStack.push( curr->right ); } 13 if( curr->left ) { nodesStack.push( curr->left ); } 14 } 15 return result; 16 } 17 };
Binary Tree Preorder Traversal,布布扣,bubuko.com
Binary Tree Preorder Traversal
标签：des style blog color io strong for ar
原文地址：http://www.cnblogs.com/moderate-fish/p/3904269.html
