104. Maximum Depth of Binary Tree


Given a binary tree, find its maximum depth.

The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.

同Minimum Depth of Binary Tree求解类似。 http://qiaopeng688.blog.51cto.com/3572484/1835237 


代码如下：

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/**
  * Definition for a binary tree node.
  * struct TreeNode {
  *     int val;
  *     TreeNode *left;
  *     TreeNode *right;
  *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
  * };
  */
class  Solution {
public :
     int  maxDepth(TreeNode* root) {
         int  iMaxDepth = 0;
         vector< int > depths;
         stack<TreeNode *> s;
         
         TreeNode *p,*q;
         q = NULL;
         p = root;
         if (!root)
             return  0;
         while (p != NULL || s.size() > 0)
         {
             while ( p != NULL)
             {
                 s.push(p);
                 p = p->left;
             }
             if (s.size() > 0)
             {
                 p = s.top();
                  
                 if ( NULL == p->left && NULL == p->right)
                 {
                     if (iMaxDepth < s.size())
                         iMaxDepth = s.size();
                 }
                  
                 if ( (NULL == p->right || p->right == q) )
                 {
                     q = p;
                     s.pop();
                     p = NULL;
                 }
                 else
                     p = p->right;
             }
         }
         return  iMaxDepth;
     }
};