二叉树的最近公共祖先

 * Definition for a binary tree node.
 * struct c {
 *     int val;
 *     TreeNode *left;
 *     TreeNode *right;
 *     TreeNode(int x) : val(x), left(NULL), right(NULL) {}
 * };
 */
class  {
public:
    TreeNode* result;
    bool isInside(TreeNode* root, TreeNode* p, TreeNode* q) {
        if (root == NULL) {
            return 0;
        }
        bool left, right;
        left = isInside(root->left, p, q);
        right = isInside(root->right, p, q);
        if ((right && left) || ((root == p || root == q) && (left || right))) {
             result = root;
             return 0;
         }
         if (left || right || root == p || root == q)
             return 1;
         return 0;
    }
    TreeNode* lowestCommonAncestor(TreeNode* root, TreeNode* p, TreeNode* q) {
        isInside(root, p, q);
        return result;
    }
};