[数据结构与算法]leetcode-95. 不同的二叉搜索树 II

leetcode-95. 不同的二叉搜索树 II

题目：

代码：

#include <iostream>
#include <vector>
using namespace std;

//二叉搜索树：根节点的值大于左子树所有结点的值，小于右子树所有结点的值 

struct TreeNode{
	int val;
	TreeNode *left,*right;
};

vector<TreeNode*>gTrees(int start,int end){
	if(start>end){
		return {NULL};
	}
	vector<TreeNode*> res;
	for(int i=start;i<=end;i++){
		vector<TreeNode*>leftTrees=gTrees(start,i-1);
		vector<TreeNode*>rightTrees=gTrees(i+1,end);
		for(auto& left:leftTrees){
			for(auto& right:rightTrees){
				TreeNode *currTree=new TreeNode;
				currTree->val=i;
				currTree->left=left;
				currTree->right=right;
				res.push_back(currTree);
			}
		}
	}
	return res;
} 

vector<TreeNode*> generateTrees(int n) {
	if(n==0){
		return {};
	}
	return gTrees(1,n);
}

int main(){
	vector<TreeNode*> res;
	int n;
	cin>>n;
	res=generateTrees(n);
	return 0;
}