95. Unique Binary Search Trees II

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/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ //[3,1,4,null,2,null,5],[3,1,5,null,2,4],[3,2,4,1,null,null,5],[3,2,5,1,null,4],  //failedclass Solution {public:    TreeNode* copy_tree(TreeNode* root)    {        if(!root) return NULL;        TreeNode* temp=new TreeNode(root->val);        temp->left=copy_tree(root->left);        temp->right=copy_tree(root->right);        return temp;    }    int inorder(TreeNode* root,int i)    {        if(root->left) i=inorder(root->left,i);        root->val=i++;        if(root->right) i=inorder(root->right,i);        return i;    }    void get_tree(vector<TreeNode*>& v,TreeNode* root,TreeNode* temp,int i,int n)    {        if(i>n)         {            inorder(root,1);            v.push_back(copy_tree(root));            //if(v.size()==3) cout<<root->right->right->val;            //cout<<root->left->left->val;            //v.push_back(root);            return;        }        TreeNode* tmp=new TreeNode(i);        if(temp->left) //        {            temp->right=tmp;            get_tree(v,root,temp->left,i+1,n);            if(i<n) get_tree(v,root,temp->right,i+1,n);            temp->right=NULL;        }        else        {            temp->left=tmp;            get_tree(v,root,tmp,i+1,n);            if(i<n) get_tree(v,root,temp,i+1,n);            temp->left=NULL;            temp->right=tmp;            get_tree(v,root,tmp,i+1,n);            temp->right=NULL;        }        delete tmp;    }    vector<TreeNode*> generateTrees(int n) {        if(n==0) return {};        vector<TreeNode*> v;        TreeNode* tmp=new TreeNode(1);        get_tree(v,tmp,tmp,2,n);        return v;    }};

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ //failedclass Solution {public:    TreeNode* copy_tree(TreeNode* root)    {        if(!root) return NULL;        TreeNode* temp=new TreeNode(root->val);        temp->left=copy_tree(root->left);        temp->right=copy_tree(root->right);        return temp;    }    void inorder(TreeNode* root)    {        if(root->left) inorder(root->left);        root->val++;        if(root->right) inorder(root->right);    }    void outorder(TreeNode* root)    {        if(root->left) outorder(root->left);        root->val--;        if(root->right) outorder(root->right);    }    void get_tree(vector<TreeNode*>& v,TreeNode* root,TreeNode* temp,int i,int n)    {        if(i>n)         {            //inorder(root,1);            v.push_back(copy_tree(root));            return;        }        TreeNode* tmp=new TreeNode(i);        //make it the root        tmp->left=root;        get_tree(v,tmp,tmp,i+1,n);        tmp->left=NULL;        if(temp->left&&(temp->left->left||temp->left->right))        {            inorder(root);            tmp->val=1;            tmp->right=root;            get_tree(v,tmp,temp,i+1,n);               tmp->right=NULL;            if(!root->left)            {                root->left=tmp;                get_tree(v,root,temp,i+1,n);                   root->left=NULL;            }            tmp->val=i;            outorder(root);        }        //make it the rightest        temp->right=tmp;        get_tree(v,root,tmp,i+1,n);        temp->right=NULL;        if(!temp->left&&temp!=root)        {            temp->left=tmp;            temp->val=i;            tmp->val=i-1;            get_tree(v,root,temp,i+1,n);            temp->left=NULL;            temp->val=i-1;        }        delete tmp;    }    vector<TreeNode*> generateTrees(int n) {        if(n==0) return {};        vector<TreeNode*> v;        TreeNode* tmp=new TreeNode(1);        get_tree(v,tmp,tmp,2,n);        return v;    }};

/** * Definition for a binary tree node. * struct TreeNode { *     int val; *     TreeNode *left; *     TreeNode *right; *     TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */class Solution {public:    vector<TreeNode*> get_tree(int l,int r)    {        if(l>r) return {NULL};        vector<TreeNode*> v;        for(int i=l;i<=r;i++)        {            vector<TreeNode*> left=get_tree(l,i-1);            vector<TreeNode*> right=get_tree(i+1,r);            for(auto a=left.begin();a!=left.end();a++)            {                for(auto b=right.begin();b!=right.end();b++)                {                    TreeNode* temp=new TreeNode(i);                    temp->left=*a;                    temp->right=*b;                    v.push_back(temp);                }            }        }        return v;    }    vector<TreeNode*> generateTrees(int n) {        if(n==0) return {};        return get_tree(1,n);    }};

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