先上题目: C. Cows and Sequence time limit per test 3 seconds memory limit per test 256 megabytes input standard input output standard output Bessie and the cows are playing with sequences and need your help. They start with a sequence, initially containi…

题目链接:http://codeforces.com/problemset/problem/284/C 题目意思:给出3种操作:t = 1:在前 a 个数中每个数都加上x: t= 2:在数组末尾增加一个数k,数组长度相应增加1: t = 3:删除数组最后一个数,数组长度减少1.对于n次操作,都给出整个数组所有元素的平均值. 一开始看见题目意思那么容易懂,于是以为很容易做,错足14次,15次终于成功了.先是TLE(对操作2直接暴力循环加),后在Test 10 wa wa wa~~~,说误差超了,全…

题目链接:Codeforces 486E LIS of Sequence 题目大意:给定一个数组.如今要确定每一个位置上的数属于哪一种类型. 解题思路:先求出每一个位置选的情况下的最长LIS,由于開始的想法,所以求LIS直接用线段树写了,没有改,能够用 log(n)的算法直接求也是能够的.然后在从后向前做一次类似LIS.每次推断A[i]是否小于f[dp[i]+1],这样就能够确定该位 置是否属于LIS序列. 然后为第三类的则说明dp[i] = k的仅仅有一个满足. #include <cstdi…

题目链接:http://codeforces.com/contest/284/problem/C 题意:就是给出3个操作 1)是将前i 个数加x 2)在数组最后添加一个数x 3)删除数组最后的那个数 题意:简单的线段树操作 #include <iostream> #include <cstring> #include <cstdio> using namespace std; typedef long long ll; const int M = 2e5 + 10; s…

E. Correct Bracket Sequence Editor time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Recently Polycarp started to develop a text editor that works only with correct bracket sequences (abbrev…

C. Sequence Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/gym/100114 Description Integer sequences are very interesting mathematical objects. Let us examine a sequence generated with the use of two operations: doubling and “digit…

A.Infinite Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Consider the infinite sequence of integers: 1, 1, 2, 1, 2, 3, 1, 2, 3, 4, 1, 2, 3, 4, 5.... The sequence is built in the…

题目链接: A. Infinite Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output Vasya likes everything infinite. Now he is studying the properties of a sequence s, such that its first element is…

意甲冠军: 对于数字n, 他询问是否有1~n置换 这种布置能够在产品上模每个前缀n 有可能0~n-1 解析: 通过观察1肯定要在首位,n一定要在最后 除4意外的合数都没有解 其它质数构造 a[i]=i*inv[i-1] , 这样用逆元把前面每一个数的影响都消除掉 C. Prefix Product Sequence time limit per test 1 second memory limit per test 256 megabytes input standard input outpu…

题目链接:https://codeforces.com/contest/670/problem/E 题意: 给出一个已经匹配的括号串,给出起始的光标位置(光标总是指向某个括号). 有如下操作: 1.往左移动一下光标: 2.往左移动一下光标: 3.删除当前光标指向的括号,以及和它匹配的那个括号,以及这两个括号之间的所有括号. 要求你给出在做完所有操作后的括号串. 题解: 用线段树维护,每个括号是否存在,存在记为 $1$,被删掉了记为 $0$. 然后我们只需要实现:①区间求和.②区间赋值.③根据 $…