剑指offer：树的子结构 代码实现

[code]struct TreeNode {
    int val;
    struct TreeNode *left;
    struct TreeNode *right;
    TreeNode(int x) :
            val(x), left(NULL), right(NULL) {
    }
};
class Solution {
public:
    bool HasSubtree(TreeNode* pRoot1, TreeNode* pRoot2)
    {
        bool result = false;

        if(pRoot1 != NULL && pRoot2 != NULL)
        {
            /* 如果这个节点相同，则判断是否是子树 */
            if(pRoot1->val == pRoot2->val)
            {
                result = hasTree1IncludeTree2(pRoot1,pRoot2);
            }

            /* 如果不是，接下来递归判断左子树 */
            if(result == false)
            {
                result = HasSubtree(pRoot1->left,pRoot2);
            }

            /* 如果不是，接下来递归判断右子树 */
            if(result == false)
            {
                result = HasSubtree(pRoot1->right,pRoot2);
            }
        }

        return result;
    }

    /* 判断pRoot2是否是pRoot1的子树 */
    bool hasTree1IncludeTree2(TreeNode* pRoot1, TreeNode* pRoot2)
    {

        /* 如果树2为空，则所有都匹配，查找成功 */
        if(pRoot2 == NULL)
        {
            return true;
        }

        if(pRoot1 == NULL)
        {
            return false;
        }

        if(pRoot1->val != pRoot2->val)
        {
            return false;
        }

        return hasTree1IncludeTree2(pRoot1->left,pRoot2->left) && 
                hasTree1IncludeTree2(pRoot1->right,pRoot2->right);
    }
};