Problem Statement You are given four ints: n, k, x, and y. The ints n and k describe a simple undirected graph. The graph has n nodes, numbered 1 through n. Two distinct vertices i and j are connected by an edge if and only if gcd(i, j) > k. Here, gc…
Problem Statement A string of zeros and ones is called an alternating string if no two adjacent characters are the same. Examples of alternating strings: "1", "10101", "0101010101". You are given a string s. Each character of…
Problem Statement You are given two ints: n and m. Let D be the number of permutations of the set {1,2,-,n+m} such that the first m values are not fixed points of the permutation. Formally, we are interested in permutations p such that for each j bet…
Problem Statement Alice has a string s of lowercase letters. The string is written on a wall. Alice also has a set of cards. Each card contains a single letter. Alice can take any card and glue it on top of one of the letters of s. She may use any su…
Problem Statement You are given a vector t that describes a rectangular table of zeroes and ones. Each character in t is either '0' or '1'. We say that a table is nice if there are two sequences x, y of zeroes and ones such that for each valid pair o…
周赛时遇到的一道比较有意思的题目: Problem Statement There are N rooms in Maki's new house. The rooms are numbered from 0 to N-1. Some pairs of rooms are connected by bidirectional passages. The passages have the topology of a tree. That is, there are exactly N-…
这题明明是一个简单的类似约瑟夫环的问题,但是由于细节问题迟迟不能得到正确结果,结果比赛完几分钟才改对..耻辱. 代码: #include <iostream> #include <cstdio> #include <cstring> #include <cmath> #include <algorithm> #define ll long long using namespace std; #define NN 370000 class Choo…
# [Codeforces #312 div2 A]Lala Land and Apple Trees 首先,此题的大意是在一条坐标轴上,有\(n\)个点,每个点的权值为\(a_{i}\),第一次从原点开始走,方向自选(<- or ->),在过程中,若遇到一个权值>0的点,则将此权值计入答案,并归零.当次.此方向上的所有点均为0后,输出此时的答案. 然后,进行分析: 我们很容易想到这是一个贪心,我们将正的和负的分别存入两个数组,最初的方向为: \(zhengsum > fusum…
