(algorithm) The maximum distance of two nodes of a binary tree

Topic:

Find the farthest distance of the two nodes of the binary tree.

The binary tree is defined as follows:

Class Treenode{public:    int val;    Treenode* left;    treenode* right;    TreeNode (int x): Val (x), left (null), right (null) {}};

Ideas:

Traverse each node to find the longest path at the root of the current node, and then find the maximum value in all the longest paths.

Code:

Code Listing 1:

Class Node{public:    int val;    Node* left;    node* right;    int maxleft;    int maxright;}; void longestpath_1 (node* proot,int& maxlen) {    if (proot==null)        return;    if (proot->left==null)        proot->maxleft=0;    if (proot->right==null)        proot->maxright=0;    int Leftlen;    if (proot->left) {        longestpath_1 (proot->left,maxlen);        Leftlen=1+max (proot->left->maxleft,proot->left->maxright);        proot->maxleft=leftlen;    }    int Rightlen;    if (proot->right) {        longestpath_1 (proot->right,maxlen);        Rightlen=1+max (proot->right->maxleft,proot->right->maxright);        proot->maxright=rightlen;    }    Maxlen=max (Proot->maxleft+proot->maxright,maxlen);}

Code Listing 2:

Class Treenode{public:    int val;    Treenode* left;    treenode* right;    TreeNode (int x): Val (x), left (null), right (null) {}};void Longestpath (treenode* proot,int& maxleft,int& maxright,int& maxlen) {    if (proot==null) {        maxleft=0;        maxright=0;        maxlen=0;        return;    }    int maxleft_1,maxleft_2,maxright_1,maxright_2;    Longestpath (Proot->left,maxleft_1,maxright_1,maxlen);    Longestpath (Proot->right,maxleft_2,maxright_2,maxlen);    Maxleft=1+max (maxleft_1,maxright_1);    Maxright=1+max (maxleft_2,maxright_2);    Maxlen=max (Maxleft,maxright) +1;}

(algorithm) The maximum distance of two nodes of a binary tree