题意: 给出n个数字,要求在这n个数中选出至少两个数字,使得它们的和在l,r之间,并且最大的与最小的差值要不小于x.n<=15 Problem - 550B - Codeforces 二进制 利用二进制, 第i位为1则加上a[i], 为0则不加, #include<iostream> #include <algorithm> #include <cmath> #include<map> using namespace std; typedef long…

题目传送门 /* DFS: 排序后一个一个出发往后找,找到>r为止,比赛写了return : */ #include <cstdio> #include <iostream> #include <cstring> #include <cmath> #include <algorithm> #include <vector> #include <map> #include <queue> #include…

题目传送门 /* 数学/暴力:只要一个数的最后三位能被8整除,那么它就是答案:用到sprintf把数字转移成字符读入 */ #include <cstdio> #include <algorithm> #include <cstring> #include <iostream> #include <cmath> #include <vector> using namespace std; ; const int INF = 0x3f3…

题目传送门 /* 水题:遍历一边先找AB,再BA,再遍历一边先找BA,再AB,两种情况满足一种就YES */ #include <cstdio> #include <iostream> #include <cstring> #include <cmath> #include <algorithm> #include <vector> #include <map> #include <queue> #includ…

& -- 位运算之一,有0则0 原题链接 Problem - 1514B - Codeforces 题目 Example input 2 2 2 100000 20 output 4 226732710 题意 t个测试样例,在每个样例中 数组有n个数,数字范围[ 0, 2k - 1] 使得数组每个数&后,结果=0,并且这n个数的和要尽量大 输出有多少个这样的数组 解析 数组每个数&后,结果=0  -->每一位至少一个0 数要尽量大  -->只要这一位可以 != 0, 就…

B. Preparing Olympiad Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/B Description You have n problems. You have estimated the difficulty of the i-th one as integer ci. Now you want to prepare a problemset for…

A. Two Substrings You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings "AB" and "BA" (the substrings can go in any order). Input The only line of input contains a string s of l…

A. Two Substrings time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings "AB"…

A. Two Substrings 题意:给一个字符串,求是否含有不重叠的子串"AB"和"BA",长度1e5. 题解:看起来很简单,但是一直错,各种考虑不周全,最后只能很蠢的暴力,把所有的AB和BA的位置求出来,能有一对AB和BA不重叠即可. #include <bits/stdc++.h> using namespace std; ]; vector<int> ab; vector<int> ba; int main() { w…

还是看大佬的题解吧 CFRound#753(Div.3)A-E(后面的今天明天之内补) - 知乎 (zhihu.com) 传送门  Problem - D - Codeforces 题意 n个数字,n个字符, 数字与字符一一对应, 其中字符R红色代表数字可以上升, B蓝色代表可以下降, 问一顿操作下来能否使n个数含有1~n的所有数 题解 当时真的没想到, 蓝色一定在数组前面, 红色一定在数组后面,( 反正就算有方案使得蓝不在前面, 红不在后面,蓝红也是可以交换的). 排序后, 前面的蓝色数字如果…

E. Brackets in Implications Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/E Description Implication is a function of two logical arguments, its value is false if and only if the value of the first argument is…

D. Regular Bridge Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/D Description An undirected graph is called k-regular, if the degrees of all its vertices are equal k. An edge of a connected graph is called a b…

C. Divisibility by Eight Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/C Description You are given a non-negative integer n, its decimal representation consists of at most 100 digits and doesn't contain leadin…

A. Two Substrings Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/550/problem/A Description You are given string s. Your task is to determine if the given string s contains two non-overlapping substrings "AB" and "…

http://codeforces.com/contest/426/problem/B 对称标题的意思大概是.应当指出的,当线数为奇数时,答案是线路本身的数 #include<iostream> #include<cstdio> #include<cstring> #include<algorithm> #define maxn 1005 using namespace std; char a[maxn][maxn]; int ans; void solve…

Adieu l'ami. Koyomi is helping Oshino, an acquaintance of his, to take care of an open space around the abandoned Eikou Cram School building, Oshino's makeshift residence. The space is represented by a rectangular grid of n × m cells, arranged into n…

— This is not playing but duty as allies of justice, Nii-chan! — Not allies but justice itself, Onii-chan! With hands joined, go everywhere at a speed faster than our thoughts! This time, the Fire Sisters — Karen and Tsukihi — is heading for somewher…

Even if the world is full of counterfeits, I still regard it as wonderful. Pile up herbs and incense, and arise again from the flames and ashes of its predecessor — as is known to many, the phoenix does it like this. The phoenix has a rather long lif…

Rock... Paper! After Karen have found the deterministic winning (losing?) strategy for rock-paper-scissors, her brother, Koyomi, comes up with a new game as a substitute. The game works as follows. A positive integer n is decided first. Both Koyomi a…

Palindromic characteristics of string s with length |s| is a sequence of |s| integers, where k-th number is the total number of non-empty substrings of s which are k-palindromes. A string is 1-palindrome if and only if it reads the same backward as f…

The Cartesian coordinate system is set in the sky. There you can see n stars, the i-th has coordinates (xi, yi), a maximum brightness c, equal for all stars, and an initial brightness si (0 ≤ si ≤ c). Over time the stars twinkle. At moment 0 the i-th…

Two boys decided to compete in text typing on the site "Key races". During the competition, they have to type a text consisting of s characters. The first participant types one character in v1 milliseconds and has ping t1 milliseconds. The secon…

Misha and Grisha are funny boys, so they like to use new underground. The underground has n stations connected with n - 1 routes so that each route connects two stations, and it is possible to reach every station from any other. The boys decided to h…

n people are standing on a coordinate axis in points with positive integer coordinates strictly less than 106. For each person we know in which direction (left or right) he is facing, and his maximum speed. You can put a bomb in some point with non-n…

It's hard times now. Today Petya needs to score 100 points on Informatics exam. The tasks seem easy to Petya, but he thinks he lacks time to finish them all, so he asks you to help with one.. There is a glob pattern in the statements (a string consis…

It's one more school day now. Sasha doesn't like classes and is always bored at them. So, each day he invents some game and plays in it alone or with friends. Today he invented one simple game to play with Lena, with whom he shares a desk. The rules…

链接:http://codeforces.com/contest/550/problem/A 这是我第一次玩cf这种比赛,前面做了几场练习,觉得div2的前面几个还是比较水的. 所以看到这道题我果断觉得是拼手速的题啊,结果瞬间就一发WA,连pretest都没通过, 然后开始想,发现没那么简单的样子,很多坑的样子,当我写了2个循环把AB BA 都扫一遍时, 认为考虑周全后,觉得能过了,就交,过了pretest,当时看room里面 大多数还没过A呢,觉得很高兴. 然后学长说这题能叉很多人,我不懂什么…

http://codeforces.com/problemset/problem/590/A: 在CF时没做出来,当时直接模拟,然后就超时喽. 题意是给你一个0 1串然后首位和末位固定不变,从第二项开始到倒数第二项,当前的a[i]=(a[i-1],a[i],a[i+1])三项排序后的中间项,比如连续3项为 1 0 1,那么中间的就变为1,然后题目让你输出达到稳定状态时所需的最小步数,不能的话输出-1. 无论给你啥数列,都能达到稳态.所以不可能输出-1: 还有一开始就稳定不变,或经过几次变换而稳定…

Problem - B - Codeforces 就是给你个序列, 给他整成升序的, 每次操作可以使相邻两个数交换位置, 交换条件是二数之和为奇数 结果只需输出是否可以整成升序的 思路: 需要奇数偶数分开讨论, 如果奇数和偶数都分别是单增的那么可行, 反之为no #include <bits/stdc++.h> using namespace std; typedef long long LL; typedef pair<int,int> PII; const int N = 1e…

Problem - A - Codeforces 题目 题意很简单每次操作可以使得a1 a2  a3任意两个数分别+1  -1 求最后使得a+c-2b绝对值的最小值 BUG就是最后忽略了-2和2这一点, 他们再进行一次操作就可以变成1和-1, 最后的绝对值也就是1, 所以最后的答案没有2  ! ! ! 官方代码 #include <bits/stdc++.h> using namespace std; int main() { ios_base::sync_with_stdio(0); cin…