[公开]北京市审计局2026年便携式计算机采购项目中标结果公告——中标原因深度分析

0230124/leetcode

/107. 二叉树的层序遍历 II/107. 二叉树的层序遍历 II.cpp
#include <iostream>
#include <vector>
#include <queue>
using namespace std;

class TreeNode {
public:
int val;
TreeNode* left;
TreeNode* right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

class Solution {
public:
vector<vector<int>> levelOrderBottom(TreeNode* root) {
queue<TreeNode*> q;
vector<vector<int>> res;
vector<int> level;

if (root != NULL) q.push(root);

while (!q.empty()) {
int n = q.size();
for (int i = 0; i < n; i++) {
TreeNode* cur = q.front();
q.pop();
level.push_back(cur->val);
if (cur->left) q.push(cur->left);
if (cur->right) q.push(cur->right);
}
res.push_back(level);
level.clear();
}
reverse(res.begin(), res.end());
return res;
}
};

int main() {
// 创建一个示例二叉树
TreeNode* root = new TreeNode(3);
root->left = new TreeNode(9);
root->right = new TreeNode(20);
root->right->left = new TreeNode(15);
root->right->right = new TreeNode(7);

Solution sol;
vector<vector<int>> result = sol.levelOrderBottom(root);

// 打印结果
for (const auto& level : result) {
for (int num : level) {
cout << num << " ";
}
cout << endl;
}

return 0;
}

/101. 对称二叉树/101. 对称二叉树.cpp
#include <iostream>
#include <vector>
#include <queue>
using namespace std;

// 定义二叉树节点
class TreeNode {
public:
int val;
TreeNode* left;
TreeNode* right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

// 定义二叉树
class Tree {
public:
TreeNode* root;
Tree() : root(NULL) {}
};

// 对二叉树进行层次遍历
vector<vector<int>> levelOrder(TreeNode* root) {
vector<vector<int>> result;
if (!root) return result;

queue<TreeNode*> q;
q.push(root);

while (!q.empty()) {
int size = q.size();
vector<int> level;

for (int i = 0; i < size; i++) {
TreeNode* node = q.front();
q.pop();
level.push_back(node->val);
if (node->left) q.push(node->left);
if (node->right) q.push(node->right);
}
result.push_back(level);
}
return result;
}

int main() {
// 创建一个示例二叉树
TreeNode* root = new TreeNode(3);
root->left = new TreeNode(9);
root->right = new TreeNode(20);
root->right->left = new TreeNode(15);
root->right->right = new TreeNode(7);

Tree tree;
tree.root = root;
vector<vector<int>> result = levelOrder(tree.root);

// 打印结果
for (const auto& level : result) {
for (int num : level) {
cout << num << " ";
}
cout << endl;
}

return 0;
}

/102. 二叉树的层序遍历/102. 二叉树的层序遍历.cpp
#include <iostream>
#include <vector>
#include <queue>
using namespace std;

// 定义二叉树节点
class TreeNode {
public:
int val;
TreeNode* left;
TreeNode* right;
TreeNode(int x) : val(x), left(NULL), right(NULL) {}
};

// 定义二叉树
class Tree {
public:
TreeNode* root;
Tree() : root(NULL) {}
};

// 对二叉树进行层次遍历
vector<vector<int>> levelOrderBottom(TreeNode* root) {
vector<vector<int>> result;
if (!root) return result;

queue<TreeNode*> q;
q.push(root);

while (!q.empty()) {
int size = q.size();
vector<int> level;

for (int i = 0; i < size; i++) {
TreeNode* node = q.front();
q.pop();
level.push_back(node->val);
if (node->left) q.push(node->left);
if (node->right) q.push(node->right);
}
result.push_back(level);
}

// 反转结果
reverse(result.begin(), result.end());

return result;
}

int main() {
// 创建一个示例二叉树
TreeNode* root = new TreeNode(3);
root->left = new TreeNode(9);
root->right = new TreeNode(20);
root->right->left = new TreeNode(15);
root->right->right = new TreeNode(7);

Tree tree;
tree.root = root;
vector<vector<int>> result = levelOrderBottom(tree.root);

// 打印结果
for (const auto& level : result) {
for (int num : level) {
cout << num << " ";
}
cout << endl;