Blackzxy - 博客园

LeetCode 113 Path Sum II DFS

摘要： Given the root of a binary tree and an integer targetSum, return all root-to-leaf paths where the sum of the node values in the path equals targetSum. 阅读全文

posted @ 2022-05-06 03:20 Blackzxy 阅读(13) 评论(0) 推荐(0) 编辑

Deep Learning Week3 Notes

摘要： 1. Perceptron \(\text{If }\sum_iw_ix_i+b\ge 0\) \[ \begin{align} f(x)=1 \end{align} \] \(\text{Otherwise, } f(x)=0\) \(\large \textbf{Perceptron Algor 阅读全文

posted @ 2022-05-05 04:36 Blackzxy 阅读(20) 评论(0) 推荐(0) 编辑

LibreOJ 131 树状数组2：区间修改，单点查询

摘要：题目地址 Solution 前面已经知道了树状数组的单点修改和区间查询。这里利用差分的思想：具体来说，维护 \(b\) 数组： \[ b[i] = a[i]-a[i-1] \] 其中 \(a\) 为原来数组。可以发现 \[ a[i] = \sum_{k=1}^ib[k] \] 因此我们只需要对 \( 阅读全文

posted @ 2022-05-03 03:11 Blackzxy 阅读(32) 评论(0) 推荐(0) 编辑

机器学习中的优化 Optimization Chapter 3 Projected Gradient Descent(1)

摘要： 1. Projected Gradient Descent \[ \begin{align} y_{t+1} &= x_t-\gamma \nabla f(x_t)\\ x_{t+1} &= \prod_X(y_{t+1}) = \arg\min_{x}||x-y_{t+1}||^2 \end{al 阅读全文

posted @ 2022-05-02 23:35 Blackzxy 阅读(111) 评论(0) 推荐(0) 编辑

LeetCode 62 Unique Paths DP

摘要： There is a robot on an m x n grid. The robot is initially located at the top-left corner (i.e., grid[0][0]). The robot tries to move to the bottom-rig 阅读全文

posted @ 2022-05-01 22:37 Blackzxy 阅读(52) 评论(0) 推荐(0) 编辑

LeetCode 179 Largest Number 贪心

摘要： Given a list of non-negative integers nums, arrange them such that they form the largest number and return it. Since the result may be very large, so 阅读全文

posted @ 2022-05-01 22:28 Blackzxy 阅读(16) 评论(0) 推荐(0) 编辑

LeetCode 55 Jump Game 贪心

摘要： You are given an integer array nums. You are initially positioned at the array's first index, and each element in the array represents your maximum ju 阅读全文

posted @ 2022-05-01 03:01 Blackzxy 阅读(18) 评论(0) 推荐(0) 编辑

LeetCode 45 Jump Game II 区间DP

摘要： Given an array of non-negative integers nums, you are initially positioned at the first index of the array. Each element in the array represents your 阅读全文

posted @ 2022-05-01 02:36 Blackzxy 阅读(21) 评论(0) 推荐(0) 编辑

Deep Learning Week2 Notes

摘要： Loss and Risk 1. Classification & Regression \(\text{I. Classification(e.g. }{\bf{Objection\ recognition, cancer\ detection, speech\ processing...}})\ 阅读全文

posted @ 2022-04-30 16:26 Blackzxy 阅读(21) 评论(0) 推荐(0) 编辑

机器学习中的优化 Optimization Chapter 2 Gradient Descent(2)

摘要： \(\large \bf{Theorem }\ 2.7:\) \(f:\mathbb{R^d}\rightarrow\mathbb{R}\text{ be convex and differentiable with a global minimum }x^*;\text{ Suppose }f\t 阅读全文

posted @ 2022-04-29 02:54 Blackzxy 阅读(33) 评论(0) 推荐(0) 编辑

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