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−…

题意 给定一棵 \(n\) 个点的带点权树,以 \(1\) 为根, \(m\) 次询问,每次询问给出两个值 \(p, k\) ,求以下值: \(p\) 的子树中距离 \(p \le k\) 的所有点权最小值,询问强制在线. \(n \le 10^5 , m \le 10^6, TL = 6s\) 题解 如果不强制在线,直接线段树合并就做完了. 强制在线,不难想到用一些可持久化的结构来维护这些东西. 其实可以类似线段树合并那样考虑,也就是说每次合并的时候我们依然使用儿子的信息. 只要在合并 \(x…

A.每个状态只有一种后续转移,判断每次转移是否都合法即可. #include <iostream> #include <cstdio> using namespace std; ], n; bool check(int x){ ] == x) return false; ], r = x, s = -a[]-x; ; i <= n; i++){ if(a[i] == s) return false; l = a[i]; r = s; s = -l-r; } return tr…

总的来说这套题还是很不错的,让我对主席树有了更深的了解 A:水题,模拟即可 #include<bits/stdc++.h> #define fi first #define se second #define mp make_pair #define pb push_back #define pi acos(-1.0) #define ll long long #define mod 1000000007 #define C 0.5772156649 #define ls l,m,rt<…

D. Credit Card time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Recenlty Luba got a credit card and started to use it. Let's consider n consecutive days Luba uses the card. She starts with …

C. Rumor time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Vova promised himself that he would never play computer games... But recently Firestorm — a well-known game developing company — pu…

B. Beautiful Divisors time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Recently Luba learned about a special kind of numbers that she calls beautiful numbers. The number is called beautiful…

A. Chess For Three time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alex, Bob and Carl will soon participate in a team chess tournament. Since they are all in the same team, they have decide…

A. Chess For Three time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Alex, Bob and Carl will soon participate in a team chess tournament. Since they are all in the same team, they have decide…

D. Credit Card Recenlty Luba got a credit card and started to use it. Let's consider n consecutive days Luba uses the card. She starts with 0 money on her account. In the evening of i-th day a transaction ai occurs. If ai > 0, then ai bourles are dep…

C. Rumor Vova promised himself that he would never play computer games... But recently Firestorm — a well-known game developing company — published their newest game, World of Farcraft, and it became really popular. Of course, Vova started playing it…

B. Beautiful Divisors Recently Luba learned about a special kind of numbers that she calls beautiful numbers. The number is called beautiful iff its binary representation consists of k + 1 consecutive ones, and then k consecutive zeroes. Some example…

A. Chess For Three Alex, Bob and Carl will soon participate in a team chess tournament. Since they are all in the same team, they have decided to practise really hard before the tournament. But it's a bit difficult for them because chess is a game fo…

D. Stressful Training 题目链接:https://codeforces.com/contest/1132/problem/D 题意: 有n台电脑,每台电脑都有初始电量ai,也有一个耗电量bi,意即每1s耗电多少,现在你有一个充电器,它每s可以给一台电脑充x的点亮. 问x最少为多少,可以让所有电脑直至k时刻,点亮都不小于0. 题解: 我们考虑贪心,先给最需要充电的电脑充电,然后二分答案x去检验.大概思路就是这样吧...但是实现起来还是有点困难. 首先处理出每个电脑最晚需要充电的…

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…

Educational Codeforces Round 39 (Rated for Div. 2) G 题意: 给一个序列\(a_i(1 <= a_i <= 10^{9}),2 <= n <= 200000\), 如果至多删除其中的一个数之后该序列为严格上升序列,那么称原序列为几乎严格上升序列. 现在每次将序列中的任意数字变成任意数字,问最少要操作几次才能将序列变成几乎严格上升子序列. 思路: 如果不考虑删除,求让整个序列都变成严格上升子序列的次数 求出\(序列a_i - i\)…

Educational Codeforces Round 48 (Rated for Div. 2) C. Vasya And The Mushrooms 题目链接:https://codeforces.com/contest/1016/problem/C 题意: emmm,说不清楚,还是直接看题目吧. 题解: 这个题人行走的方式是有一定的规律的,最后都是直接走到底,然后从另外一行走回来.并且通过画图观察,会发现他走到格子的时间会有一定的规律. 所以就维护几个前缀和就行了,从1到n枚举一下,还要…

Educational Codeforces Round 60 (Rated for Div. 2) 题目链接:https://codeforces.com/contest/1117 A. Best Subsegment 题意: 给出n个数,选取一段区间[l,r],满足(al+...+ar)/(r-l+1)最大,这里l<=r,并且满足区间长度尽可能大. 题解: 因为l可以等于r,所以我们可以直接考虑最大值,因为题目要求,直接求连续的最大值的长度就是了. 代码如下: #include <bits…

Educational Codeforces Round 59 (Rated for Div. 2) D. Compression 题目链接:https://codeforces.com/contest/1107/problem/D 题意: 给出一个n*(n/4)的矩阵,这个矩阵原本是一些01矩阵,但是现在四个四个储存进二进制里面,现在给出的矩阵为0~9以及A~F,表示0~15. 然后问这个矩阵能否压缩为一个(n/x)*(n/x)的矩阵,满足原矩阵中大小为x*x的子矩阵所有数都相等(所有子矩阵构…

Educational Codeforces Round 58 (Rated for Div. 2)  题目总链接:https://codeforces.com/contest/1101 A. Minimum Integer 题意: 多组数据,给你三个数l,r,d,要求在区间[l,r]之外找一个最小的x,使得x%d==0. 题解: 当d<l or d>r的时候,直接输出d就好了. 当l<=d<=r的时候,找到最小的t,使得t*d>r就行了. 具体操作见代码: #include…

Educational Codeforces Round 34 (Rated for Div. 2) A Hungry Student Problem 题目链接: http://codeforces.com/contest/903/problem/A 思路: 直接模拟 代码: #include <bits/stdc++.h> using namespace std; int main() { int n; scanf("%d",&n); while(n--) { i…

Educational Codeforces Round 69 (Rated for Div. 2) E. Culture Code 题目链接 题意: 给出\(n\)个俄罗斯套娃,每个套娃都有一个\(in_i,out_i\),并满足\(out_i>in_i\).定义套娃\(i\)能套在套娃\(j\)里面,当且仅当\(out_i\leq in_j\). 定义极大套娃组:当且仅当不能有另外一个套娃套在它们身上. 定义套娃组额外空间为\(in_1+(in_2-out_1)+\cdots +(in_k-…

Educational Codeforces Round 65 (Rated for Div. 2)题解 题目链接 A. Telephone Number 水题,代码如下: Code #include <bits/stdc++.h> using namespace std; typedef long long ll; const int N = 2e5 + 5; int a[N] ; int n, T; char s[N] ; int main() { cin >> T; whil…

Educational Codeforces Round 64 (Rated for Div. 2)题解 题目链接 A. Inscribed Figures 水题,但是坑了很多人.需要注意以下就是正方形.圆以及三角形的情况,它们在上面的顶点是重合的. 其余的参照样例判断一下就好了了.具体证明我也不会 代码如下: Code #include <bits/stdc++.h> using namespace std; typedef long long ll; const int N = 2e5 +…