LCA.cpp

#include <iostream>
using namespace std;

struct TreeNode {
    int val;
    TreeNode *left, *right;
    TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

TreeNode* LCA(TreeNode* root, TreeNode* p, TreeNode* q) {
    if (!root || root == p || root == q) return root;
    TreeNode* left = LCA(root->left, p, q);
    TreeNode* right = LCA(root->right, p, q);
    if (left && right) return root;
    return left ? left : right;
}

int main() {
    TreeNode* root = new TreeNode(3);
    root->left = new TreeNode(5);
    root->right = new TreeNode(1);
    root->left->left = new TreeNode(6);
    root->left->right = new TreeNode(2);
    root->right->left = new TreeNode(0);
    root->right->right = new TreeNode(8);

    TreeNode* p = root->left;      
    TreeNode* q = root->right;     

    cout << "LCA: " << LCA(root, p, q)->val << endl;
}