原文:https://medium.com/rungo/anatomy-of-channels-in-go-concurrency-in-go-1ec336086adb -------------------------------- What are the channels? A channel is a communication object using which goroutines can communicate with each other. Technically, a ch…

SQFREE - Square-free integers 求n以内,约数中不包含任意一个平方数的个数,\(n≤10^{14}\). 解 显然为约数计数问题,于是想办法转换为代数问题,不难列出 \[ans=\sum_{i=1}^n\mu^2(i)\] 没有gcd,不好反演,考虑容斥,则有 \[ans=\sum_{i=1}^{\sqrt{n}}\mu(i)[n/i^2]\] 以此即可解决问题,时间复杂度\(O(\sqrt{n})\). 参考代码: #include <iostream> #inc…

A. Plus and Square Root time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output ZS the Coder is playing a game. There is a number displayed on the screen and there are two buttons, ' + ' (plus) an…

Square Time Limit : 10000/5000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other) Total Submission(s) : 9   Accepted Submission(s) : 4 Problem Description Given a set of sticks of various lengths, is it possible to join them end-to-end to form…

[Educational Codeforces Round 16]C. Magic Odd Square 试题描述 Find an n × n matrix with different numbers from 1 to n2, so the sum in each row, column and both main diagonals are odd. 输入 The only line contains odd integer n (1 ≤ n ≤ 49). 输出 Print n lines…

Square Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others) Total Submission(s): 11151    Accepted Submission(s): 3588 Problem Description Given a set of sticks of various lengths, is it possible to join them end-to-en…

Square Time Limit: 10000/5000 MS (Java/Others)    Memory Limit: 65536/32768 K (Java/Others)Total Submission(s): 5443    Accepted Submission(s): 1732 Problem Description Given a set of sticks of various lengths, is it possible to join them end-to-end…

E. Square Root of Permutation A permutation of length n is an array containing each integer from 1 to n exactly once. For example, q = [4, 5, 1, 2, 3] is a permutation. For the permutation q the square of permutation is the permutation p that p[i] = …

Square TimeLimit: 1 Second   MemoryLimit: 32 Megabyte Totalsubmit: 1638   Accepted: 440 Description Given a set of sticks of various lengths, is it possible to join them end-to-end to form a square? Input The first line of input contains N, the numbe…

Square Time Limit : 10000/5000ms (Java/Other)   Memory Limit : 65536/32768K (Java/Other) Total Submission(s) : 20   Accepted Submission(s) : 12 Font: Times New Roman | Verdana | Georgia Font Size: ← → Problem Description Given a set of sticks of vari…