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diameter_of_binary_tree.cpp
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diameter_of_binary_tree.cpp
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//Path with highest number of nodes is the diameter of a binary tree
/*
Given a binary tree, you need to compute the length of the diameter of the tree.
The diameter of a binary tree is the length of the longest path between any two nodes in a tree. This path may or may not pass through the root.
Example:
Given a binary tree
1
/ \
2 3
/ \
4 5
Return 3, which is the length of the path [4,2,1,3] or [5,2,1,3].
*/
//Solution 1
class Solution {
public:
int diameterOfBinaryTree(TreeNode* root) {
if(root==NULL)
return 0;
int option1=height(root->left)+height(root->right);
int option2=diameterOfBinaryTree(root->left);
int option3=diameterOfBinaryTree(root->right);
return max(option1, max(option2, option3));
}
int height(TreeNode* root)
{
if(root==NULL)
return 0;
return 1+max(height(root->left),height(root->right));
}
//Solution 2
class Solution {
public:
int ans=0;
int diameterOfBinaryTree(TreeNode* root)
{
if(root==nullptr)
return 0;
int left_subtree_height=height(root->left);
int right_subtree_height=height(root->right);
ans=max(ans, left_subtree_height+right_subtree_height+1);
diameterOfBinaryTree(root->left);
diameterOfBinaryTree(root->right);
return ans-1;
}
int height(TreeNode* root)
{
if(root==nullptr)
return 0;
return 1+max(height(root->left),height(root->right));
}
};