Beru-taxi 题目链接: http://codeforces.com/contest/706/problem/A Description Vasiliy lives at point (a, b) of the coordinate plane. He is hurrying up to work so he wants to get out of his house as soon as possible. New app suggested n available Beru-taxi…

Codeforces Round #575 (Div. 3) 这个div3打的太差了,心态都崩了. B. Odd Sum Segments B 题我就想了很久,这个题目我是找的奇数的个数,因为奇数想分成x个奇数,那么这个x肯定是一个奇数, 偶数同理,如果一个偶数想分成y个奇数,那么这个y肯定是一个偶数. 所以数奇数的个数,如果奇数有x个,x是偶数,那么k一定是一个偶数,如果x是一个奇数,那么k肯定是一个奇数. 输出也比较简单,因为奇数要分成奇数个,所以可以前面每组都是含有一个奇数,最后肯定会有奇…

[感谢牛老板对D题的指点OTZ] codeforces 842 A. Kirill And The Game[暴力] 给定a的范围[l,r],b的范围[x,y],问是否存在a/b等于k.直接暴力判断即可. #include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> using namespace std; typede…

A. Uncowed Forces Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/604/problem/A Description Kevin Sun has just finished competing in Codeforces Round #334! The round was 120 minutes long and featured five problems with maxi…

http://codeforces.com/contest/842/problem/C 树 dp 一个数的质因数有限,用set存储,去重 #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <time.h> #include <string> #include <set> #include <map>…

http://codeforces.com/contest/842/problem/D 树 二进制(路径,每个节点代表一位) #include <cstdio> #include <cstdlib> #include <cmath> #include <cstring> #include <time.h> #include <string> #include <set> #include <map> #incl…

地址:http://codeforces.com/contest/842/problem/C 题目: C. Ilya And The Tree time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Ilya is very fond of graphs, especially trees. During his last trip…

题目链接:http://codeforces.com/contest/842/problem/D 题意:定义Mex为一个序列中最小的未出现的正整数,给定一个长度为n的序列,然后有m个询问,每个询问给定一个数x,先对序列每个数与x进行异或运算(^),之后输出当前序列修改完之后的Mex. 思路:因为对于原序列和x异或后,得到的新序列再与y异或相当于原序列与z(z=x^y)进行异或,所以问题就可以转化为对于一个数val,原序列和val进行异或后得到新序列的Mex是多少? 考虑01字典树,先把序列的n个…

题目链接:http://codeforces.com/contest/842/problem/B 题意:给定一个圆心在原点(0,0)半径为r的大圆和一个圆内的圆环长度d,然后给你n个小圆,问你有多少个小圆完全位于圆环中 思路:求出每个小圆的圆心和原点的距离dist. 如果满足dist[i]-r[i]>=(r-d)&&dist[i]+r[i]<=r,说明这个小圆完全位于圆环. #define _CRT_SECURE_NO_DEPRECATE #include<iostrea…

题目链接:http://codeforces.com/contest/842/problem/A 题意:给定l,r,x,y,k.问是否存在a (l<=a<=r) 和b (x<=b<=y) 使得 a/b=k (a/b可能为浮点数). 思路:暴力枚举即可. #define _CRT_SECURE_NO_DEPRECATE #include<iostream> #include<cstring> #include<string> #include<…

A. Kirill And The Game time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output Kirill plays a new computer game. He came to the potion store where he can buy any potion. Each potion is characteriz…

因为抑或,一眼字典树 但是处理起来比较难 #include<iostream> #include<map> #include<iostream> #include<cstring> #include<cstdio> #include<set> #include<vector> #include<queue> #include<stack> #include<cmath> #include…

·不论难度,A,C,D自己都有收获! [A. Kirill And The Game] ·全是英文题,述大意:    给出两组区间端点:l,r,x,y和一个k.(都是正整数,保证区间不为空),询问是否在[x,y]区间内存在一个整数p,使得p*k属于[l,r],如果存在,则输出'YES',否则输出'NO'.(1<=l,r,x,y<=107) ·分析:     首先看见了107,发现可以直接O(n)暴力枚举:枚举区间[x,y]的所有数,判断它与k的乘积是否在[l,r]中就可以了.从容AC: #in…

D.Vitya and Strange Lesson(字典树) 题意: 给一个长度为\(n\)的非负整数序列,\(m\)次操作,每次先全局异或\(x\),再查询\(mex\) \(1<=n<=3e5\) \(0<=a_i<=3e5\) \(0<=x<=3e5\) 思路:求\(mex\)可以通过按从高位到低位建字典树,判断左子树是否满,若未满,贪心往走,否则往右走,这样查询是\(log\)的 现在就是异或修改,考虑x的第i位,若为1,则以第i-1层结点为根的左右子树都需要…

[链接]点击打开链接 [题意] 水题 [题解] 枚举b从x..y看看k*i是不是在l..r之间就好. [错的次数] 0 [反思] 在这了写反思 [代码] #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> #include <vector> #include <map> #include <queue> #include…

[链接]点击打开链接 [题意] 在这里写题意 [题解] 根据圆心到原点的距离这个东西判断一下圆在不在那个环里面就好 [错的次数] 0 [反思] 在这了写反思 [代码] #include <cstdio> #include <iostream> #include <algorithm> #include <cstring> #include <vector> #include <map> #include <queue> #…

[链接]点击打开链接 [题意] 给你一棵n个点的树,每个点的美丽值定义为根节点到这个点的路径上的所有权值的gcd. 现在,假设对于每一个点,在计算美丽值的时候,你可以将某一个点的权值置为0的话. 问你每个点的最大美丽值可能是多少. [题解] 从根节点开始进行dfs,在往下走的过程中,暴力用set记录下路径中把以上的每一个点删掉后的gcd是什么. 这set里的东西.进行扩展的时候,只能加入不删的点.因为它已经表示删掉一个点的状态了.下面只能都不删 了.然后用另外一个数组now,记录下到根节点到当前…

[链接]点击打开链接 [题意] 给出一个数组,每次操作将整个数组亦或一个数x,问得到的数组的结果中的mex.mex表示为自然数中第一个没有出现过的数. [题解] 异或的效果是可以累加的,所以不用每次都算出来每一次的a是什么.而只要把前i个询问的x取一下异或和now,然后用异或和对每个ai异或就可以了. 对于这道题.我们需要用字典树来做. 对于一开始的a数组中没有出现的数字,都把它按照位加入到字典树中,最多19位. 设原数组是a,然后没出现的数字组成数组A. 结论:则我们对原数组进行一次异或操作即…

A. Wizards' Duel Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/591/problem/A Description Harry Potter and He-Who-Must-Not-Be-Named engaged in a fight to the death once again. This time they are located at opposite ends of…

A. LCM Challenge 题目连接: http://www.codeforces.com/contest/235/problem/A Description Some days ago, I learned the concept of LCM (least common multiple). I've played with it for several times and I want to make a big number with it. But I also don't wa…

B. Testing Robots Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://www.codeforces.com/contest/606/problem/B Description The Cybernetics Failures (CF) organisation made a prototype of a bomb technician robot. To find the possible problems it was de…

A. Magic Spheres Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://www.codeforces.com/contest/606/problem/A Description Carl is a beginner magician. He has a blue, b violet and c orange magic spheres. In one move he can transform two spheres of the…

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 "…

A. Even Odds Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/318/problem/A Description Being a nonconformist, Volodya is displeased with the current state of things, particularly with the order of natural numbers (natural n…

题目链接:http://codeforces.com/contest/675/problem/C 给你n个bank,1~n形成一个环,每个bank有一个值,但是保证所有值的和为0.有一个操作是每个相邻的bank之间可以转钱,让你用最少的操作使每个bank的值为0. 一开始没什么思路,看了一下别人的题解,果然还是还是native... 要是让操作次数变少,首先划分和为0的区间个数要尽量多,比如一个区间的长度为k,那么他操作次数为k - 1,所以总的操作次数就是(n - 区间的个数). 那么要算出区…

A. Two Bases Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/602/problem/A Description After seeing the "ALL YOUR BASE ARE BELONG TO US" meme for the first time, numbers X and Y realised that they have different bases,…

A. Calculating Function Time Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/486/problem/A Description For a positive integer n let's define a function f: f(n) =  - 1 + 2 - 3 + .. + ( - 1)nn Your task is to calculate f(n) for a…

A. Lineland MailTime Limit: 20 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/567/problem/A Description All cities of Lineland are located on the Ox coordinate axis. Thus, each city is associated with its position xi — a coordinate on th…

B. Luxurious Houses Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/581/problem/B Description The capital of Berland has n multifloor buildings. The architect who built up the capital was very creative, so all the houses wer…

A. Multiplication Table Time Limit: 1 Sec Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/577/problem/A Description Let's consider a table consisting of n rows and n columns. The cell located at the intersection of i-th row and j-th column co…