Question

write a 3 recursive functions in C that return the sum, min and max of a binary tree.

Answer 1

struct Node {
int data;
struct Node *left;
struct Node *right;
};

int sum (struct Node *node) {
if (node == 0)
return 0;

return node->data + sum (node->left) + sum (node->right);
}

// Returns maximum value in a given Binary Tree
int max(struct node* root)
{
// Base case
if (root == NULL)
return INT_MIN;

// Return maximum of 3 values:
// 1) Root's data 2) Max in Left Subtree
// 3) Max in right subtree
int res = root->data;
int lres = max(root->left);
int rres = max(root->right);
if (lres > res)
res = lres;
if (rres > res)
res = rres;
return res;
}

// Returns minimum value in a given Binary Tree
int min(struct node* root)
{
// Base case
if (root == NULL)
return INT_MAX;

// Return minimum of 3 values:
// 1) Root's data 2) Max in Left Subtree
// 3) Max in right subtree
int res = root->data;
int lres = min(root->left);
int rres = min(root->right);
if (lres < res)
res = lres;
if (rres < res)
res = rres;
return res;
}