题目链接 题意:给你两个数x,yx,yx,y,让你构造一些长为yyy的数列,让这个数列的累乘为xxx,输出方案数. 思路:考虑对xxx进行质因数分解,设某个质因子PiP_iPi​的的幂为kkk,则这个质因子的贡献就相当于把kkk个PiP_iPi​放到yyy个盒子中,且盒子可能为空,方案为C(k+y−1,y)C(k+y-1,y)C(k+y−1,y),然后每个质因子的方案乘在一起即可.最后,因为负号也会出现,但xxx为正,所以就是在yyy个位置上选偶数个位置放负号,方案为2y−12^{y-1}2y−…

比赛链接 A 题解 知识点:贪心. 注意到 \(m\geq n\) 时,不存在某一行或列空着,于是不能移动. 而 \(m<n\) 时,一定存在,可以移动. 时间复杂度 \(O(1)\) 空间复杂度 \(O(1)\) 代码 #include <bits/stdc++.h> #define ll long long using namespace std; bool solve() { int n, m; cin >> n >> m; for (int i = 1;i…

求a_i 在 [1,k]范围内,gcd(a_1,a_2...,a_n) = 1的a的数组个数. F(x)表示gcd(a_1,a_2,...,a_n) = i的a的个数 f(x)表示gcd(a_1,a_2,...,a_n) = ki的a的个数(实际上就是i的倍数) f(x) = segma(x | d) F(d) F(x) = segma(x | d) mu(d / x) * f(d) F(1) = segma(d,1,k) mu(d) * f(d) f(d) = (k / d)^n 由于k变化时…

Problem   Educational Codeforces Round 60 (Rated for Div. 2) - C. Magic Ship Time Limit: 2000 mSec Problem Description Input Output The only line should contain the minimal number of days required for the ship to reach the point (x2,y2)(x2,y2). If it…

Problem   Educational Codeforces Round 60 (Rated for Div. 2) - D. Magic Gems Time Limit: 3000 mSec Problem Description Input The input contains a single line consisting of 2 integers N and M (1≤N≤10^18, 2≤M≤100). Output Print one integer, the total n…

Educational Codeforces Round 43 (Rated for Div. 2) https://codeforces.com/contest/976 A #include<bits/stdc++.h> using namespace std; #define lson l,mid,rt<<1 #define rson mid+1,r,rt<<1|1 #define IT set<ll>::iterator #define sqr(x)…

Educational Codeforces Round 35 (Rated for Div. 2) https://codeforces.com/contest/911 A 模拟 #include<bits/stdc++.h> using namespace std; #define lson l,mid,rt<<1 #define rson mid+1,r,rt<<1|1 #define IT set<ll>::iterator #define sqr(…

Codeforces Educational Codeforces Round 44 (Rated for Div. 2) F. Isomorphic Strings 题目连接: http://codeforces.com/contest/985/problem/F Description You are given a string s of length n consisting of lowercase English letters. For two given strings s an…

Codeforces Educational Codeforces Round 44 (Rated for Div. 2) E. Pencils and Boxes 题目连接: http://codeforces.com/contest/985/problem/E Description Mishka received a gift of multicolored pencils for his birthday! Unfortunately he lives in a monochrome w…

Educational Codeforces Round 63 (Rated for Div. 2)题解 题目链接 A. Reverse a Substring 给出一个字符串,现在可以对这个字符串进行一次翻转,问是否存在一种方案,可以使得翻转后字符串的字典序可以变小.   这个很简单,贪心下就行了. 代码如下: Code #include <bits/stdc++.h> using namespace std; typedef long long ll; const int N = 3e5…