ARTS-week16

Algorithms

/**
 * 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<vector<int>> levelOrder(TreeNode* root) {
        if (root == NULL) {
            return res;
        }
        preorder(root, 0);
        return res;
    }
private:
    vector<vector<int>> res;
    
    void preorder(TreeNode* root, int level) {
        while (res.size() <= level) {
            res.push_back(vector<int>());
        }
        res[level].push_back(root->val);
        if (root->left != NULL) {
            preorder(root->left, level + 1);
        }
        if (root->right != NULL) {
            preorder(root->right, level + 1);
        }
    }
};

Binary Tree Level Order Traversal II

/**
 * 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<vector<int>> levelOrderBottom(TreeNode* root) {
        if (root == NULL) {
            return res;
        }
        levelOrder(root, 0);
        reverse(res.begin(), res.end());
        return res;
    }
private:
    vector<vector<int>> res;
    void levelOrder(TreeNode* root, int level) {
        if (res.size() <= level) {
            res.push_back(vector<int>());
        }
        res[level].push_back(root->val);
        if (root->left != NULL) {
            levelOrder(root->left, level + 1);
        }
        if (root->right != NULL) {
            levelOrder(root->right, level + 1);
        }
    }
};

Review

本周阅读英文文章 A new class of zero days and autonomous weapons systems

Adversarial examples are inputs to machine learning models that an attacker has intentionally designed to cause the model to make a mistake; they’re like optical illusions for machines.

Using the same zero day logic, adversarial training attempts to train the artificial intelligence algorithm to recognise false positives, and react in the way that it was designed even when hostile actors try to trick the artificial intelligence. But just like with code, the creators of the algorithm and the testers of the algorithm may not have thought of all the ways in which hostile actors can trick the AI.