树的子结构.cpp

/* *************************
 * 树的子结构（代码鲁棒性）
 * 输入两颗二叉树A，B，判断B是不是A的子结构。
 * *************************/
struct TreeNode {
  int val;
  struct TreeNode *left;
  struct TreeNode *right;
  TreeNode(int x) :
      val(x), left(NULL), right(NULL) {
  }
};
class Solution {
public:
    bool DoesTree1HasTree2(TreeNode* pRoot1, TreeNode* pRoot2){
        if (pRoot2==NULL)
            return true;
        if (pRoot1==NULL)
            return false;

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

        return DoesTree1HasTree2(pRoot1->left, pRoot2->left) && DoesTree1HasTree2(pRoot1->right, pRoot2->right);
    }
  bool HasSubtree(TreeNode* pRoot1, TreeNode* pRoot2)
  {
        bool result = false;

        if(pRoot1!=NULL && pRoot2!=NULL){
            if(pRoot1->val == pRoot2->val)
                result = DoesTree1HasTree2(pRoot1, pRoot2);
            if(!result)
                result = HasSubtree(pRoot1->left, pRoot2);
            if(!result)
                result = HasSubtree(pRoot1->right, pRoot2);
        }

        return result;

  }
};