701 二叉搜索树中的插入 *** 作

二叉搜索树的插入，只要到规定的节点位置新建一个叶节点就可以了。

#include
#include
#include
using namespace std;
struct TreeNode {
    int val;
    TreeNode *left;
    TreeNode *right;
    TreeNode() : val(0), left(nullptr), right(nullptr) {}
    TreeNode(int x) : val(x), left(nullptr), right(nullptr) {}
    TreeNode(int x, TreeNode *left, TreeNode *right) : val(x), left(left), right(right) {}
};
class Solution {
public:
    TreeNode* insertIntoBST(TreeNode* root, int val) {
        TreeNode* ans = new TreeNode(val);
        if (root == nullptr)return ans;
        TreeNode* p = root;
        while (p != nullptr) {
            if (val < p->val) {
                if (p->left == nullptr) {
                    p->left = ans;
                    break;
                }
                else p = p->left;
            }
            else {
                if (p->right == nullptr) {
                    p->right = ans;
                    break;
                }
                else p = p->right;
            }
        }
        return root;   
    }
};
void print(TreeNode* a) {
    if(a != nullptr){
        cout << a->val;
        print(a->left);
        print(a->right);
    }
}
int main() {
    Solution test;
    TreeNode* c = new TreeNode(1);
    TreeNode* b = new TreeNode(3);
    TreeNode* a = new TreeNode(2,c, b);
    print(test.insertIntoBST(a, 5));
}