子树

class Solution {
public:
    /**
     * @param T1, T2: The roots of binary tree.
     * @return: True if T2 is a subtree of T1, or false.
     */
     
    bool nua;
    bool xx;
    bool trade(TreeNode *x)
    {
        if(x==NULL)
        return 0;
        return 1;
    }
    void look2(TreeNode *a,TreeNode *b)
     {
    
         if(a==NULL||b==NULL)
         return;
         if(a->val!=b->val)
         {  
             xx=0;
             return ;
         }
         if(trade(a->left)!=trade(b->left)||trade(a->right)!=trade(b->right))
         { xx=0;return; }
            look2(a->left,b->left);
            look2(a->right,b->right);
     }
    
    void look(TreeNode *x,TreeNode *x1)
    {
        if(x==NULL)
        return;
        if(nua==1)
        return;
        if(x->val==x1->val&&nua!=1)
       {   xx=1;
           look2(x,x1);
       }
       if(xx==1)
       nua=1; 
        look(x->left,x1);
        look(x->right,x1);
    }
    bool isSubtree(TreeNode *T1, TreeNode *T2) {
        nua=0;
        xx=0;
        if(T2==NULL)
        return true;
        look(T1,T2);
        return nua;
        // write your code here
    }
};