Data Structure Binary Tree: Diameter of a Binary Tree

http://www.geeksforgeeks.org/diameter-of-a-binary-tree/

 1 #include <iostream>

 2 #include <vector>

 3 #include <algorithm>

 4 #include <queue>

 5 #include <stack>

 6 using namespace std;

 7 

 8 struct node {

 9     int data;

10     struct node *left, *right;

11     node() : data(0), left(NULL), right(NULL) { }

12     node(int d) : data(d), left(NULL), right(NULL) { }

13 };

14 

15 void print(node *node) {

16     if (!node) return;

17     print(node->left);

18     cout << node->data << " ";

19     print(node->right);

20 }

21 

22 int diameter(node *root, int &ans) {

23     if (!root) return 0;

24     int l = diameter(root->left, ans);

25     int r = diameter(root->right, ans);

26     ans = max(ans, l+r+1);

27     return max(l, r) + 1;

28 }

29 

30 

31 int main() {

32     struct node* root = new node(1);

33     root->left = new node(2);

34     root->right = new node(3);

35     root->left->left = new node(4);

36     root->left->right = new node(5);

37     int ans = 0;

38     diameter(root, ans);

39     cout << ans << endl;

40     return 0;

41 }