并查集 框架如下 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 class UF: def __init__(self, N): self.N = N self._id = [i for i in range(N)] def find(self, p): while p != self._id[p]: p = self._id[p] return p def union(self, p, q): p = self.find(p) q = self.find(q) if p==q: return self._id[p] = q……

Open schools first The new scold war ……

MD5 Algorithm 一个最小的MD5算法(md5.c) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 #include <stdint.h> void md5_compress(uint32_t state[static 4], const uint8_t block[static 64])……

Open schools first Open schools first……

Dynamic Programming 1. 最长上升子序列 1 2 3 4 5 6 7 8 9 10 11 12 class Solution: def lengthOfLIS(self, nums: List[int]) -> int: if len(nums) == 0: return 0 dp = [1] * len(nums) L = len(nums) for i in range(L): for j in range(i): if nums[i] > nums[j]: dp[i] = max(dp[i], dp[j]+1) return max(dp) 2. 最长公共子序列 1 2 3 4 5 6 7 8 9 10 11 12 13 class Solution: def longestCommonSubsequence(self, text1: str, text2: str) -> int: L1, L2 = len(text1), len(text2) dp = [[0] * (L1+1) for _ in range(L2+1)] for i in range(1, L2+1): for j in range(1, L1+1): if text2[i-1] == text1[j-1]: dp[i][j] = dp[i-1][j-1] + 1 else: dp[i][j] = max(dp[i-1][j], dp[i][j-1]) return dp[-1][-1] 3. 三角形最小路……

命令行的艺术 bg, fg and CTRL+Z ssh-add, ssh-agent ls -i描述符, df -i个数 dig grep -i, -v, -o, -A, -B, -C xargs pgrep, pkill lsof here documents python -m http.server 7777 128限制 ag wc, tee awk, sed, grep httpie ncdu awk sw_vers BASH ${#varname} ${varname:offset:length} ${variable#pattern} ${variable##pattern} ${path##*/} ${variable/#pattern/string} ${file%.png}.jpg ${varname^^} ${varname,,} shell $0 脚本文件名 $1 对应脚本的第一个参数 $# 参数的总数 $@ 全部的参数 read 1 2 3 4 5 6 filename='/etc/hosts' while read myline do echo "$myline" done < $filename IFS 1 2 3 4 5 input="/path/to/txt/file" while IFS= read -r line do echo "$line" done < "$input" 上面的命令可以逐……

再次思考深度学习框架的自动求导 刚开始读研的时候，对Pytorch以及Tensorflow的反向求导机制非常感兴趣，于是寻找了大量的资料去了解反向求导的机制。2017年华盛顿大学有一门课程非常棒dlsys,第一个实验关于自动求导，第二个实验关于将自动求导的矩阵计算使用GPU来操作。……

After the disease, the debt 目前的政治家对新冠以后的世界还没有做好准备。……

Is China winning? ……

The coronavirus crisis will change the world of commerce ……