The start of the new academic year brought about the problem of accommodation students into dormitories. One of such dormitories has a a?×?b square meter wonder room. The caretaker wants to accommodate exactly n students there. But the law says that there must be at least 6 square meters per student in a room (that is, the room for n students must have the area of at least 6n square meters)....
D. DZY Loves FFT time limit per test 1 second memory limit per test 256 megabytes input standard input output standard output DZY loves Fast Fourier Transformation, and he enjoys using it. Fast Fourier Transformation is an algorithm used to calculate convolution. Specifically, if a, b and ...
Peter has a sequence of integers a1,?a2,?...,?an. Peter wants all numbers in the sequence to equalh. He can perform the operation of "adding one on the segment[l,?r]": add one to all elements of the sequence with indices froml to r (inclusive). At that, Peter never chooses any element as the beginning of the segment twice. Similarly, Peter never chooses any element as the end of the segment twice....
Sergey is testing a next-generation processor. Instead of bytes the processor works with memory cells consisting of n bits. These bits are numbered from 1 to n. An integer is stored in the cell in the following way: the least significant bit is stored in the first bit of the cell, the next significant bit is stored in the second bit, and so on; the most significant bit is stored in the n-th bit. ...
D. Fedor and Essay time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output After you had helped Fedor to find friends in the Call of Soldiers 3 game, he stopped studying completely. Today, the English teacher told him to prepare an essay. F...
Codeforces Round #267 (Div. 2) A：签到题，直接for一遍 B：取异或就是不同的数，然后bitcount一下判断即可 C：dp，dp[i]表示到i的最大值，然后对取与不取当前位置进行转移即可，要先把前缀和预处理出来 D：先利用map，把字符串hash掉，然后建图，现场在做的时候是直接记忆化搜索，不过这样处理不了环的情况，果断fst了，后来换了下姿势，先求强连通进行缩点，缩点完就是一个dag了，然后记忆化搜索即可 代码： A： ...
B. Two Sets time limit per test 1 second memory limit per test 256 megabytes Little X has n distinct integers: p1,?p2,?...,?pn. He wants to divide all of them into two sets A and B. The following two conditions must be satisfied: If number x belongs to set A, then number a?-?x must al...
After you had helped George and Alex to move in the dorm, they went to help their friend Fedor play a new computer game «Call of Soldiers 3». The game has (m?+?1) players and n types of soldiers in total. Players Call of Soldiers 3 are numbered form 1 to (m?+?1). Types of soldiers are numbered from 0 to n?-?1. Each player has an army. Army of the i-th player can be described by non-n...
Codeforces Round #268 (Div. 2) 题目链接 A：有的标记掉判断一下即可 B：枚举时间一个个去判断一下即可 C：构造一下，4和5分别手动构造，然后之后每次多2个数字就先相减掉得到1，然后乘上原数字不变，4以下的是绝对构造不出来的 D：贪心，先排序，然后每次twopointer选头尾两个判断能丢进哪个集合，都不行就找一个之前满足的丢进小集合 E：推理，详细见官方题解，大致是推出来后，[x, x + 1e18 - 1]这个区间，每次挪动...
闲着没事就水了一发DIV2,本来想新注册一个小小号来着。结果验证码一直显示不出来。于是就用小号做。 结果rank44,但是没有rating. 以下均不解释题意了。 A:O(n)脑残模拟。 Code： #include int main() { int n, a, b; scanf("%d", &n); int res = 0; while(n--) { scanf("%d%d", &a, &b); if (a + 2 <= b) ++res; } printf("%d", res); return 0;} B:注意到两个数相异...
题目大意：从n个数中选出m段不相交的子串，子串的长度均为k，问所有选出来的子串的所有数的和最大为多少。 DP题，DP还是太弱，开始时的dp方程居然写成了O(n^3)... dp[i][j]: 以num[i]结尾的序列，分成j段的最大和 dp[i][j]=max(dp[k][j-1]+sum[i]-sum[i-m]) 这样的话，其实只要第一重循环是选的段数，第二重循环时数字个数 我又换了种思路 dp[i][j]: 前i个数，分成j段的最大和 dp[i][j]=max(dp[i-1][j],dp[i-m][j-1]+s...
Codeforces Round #266 (Div. 2) 题目链接 A：就简单的判断一下那种更大即可 B：枚举x到sqrt(n)，然后可以直接算出y，然后判断一下即可 C：先判断和是否是3的倍数，然后预处理出前缀和出现位置和后缀和对应sum / 3个数，然后从头往后扫一遍把当前一个和后面进行组合即可 D：先预处理出差分，使得数组表示线段的添加方式，然后每次有一个-1，就能和前面多少个1进行匹配，方案数就乘上多少，如果是0，就能和前面+1个匹配 ...
很不错的思维题，贪心 题目大意：给你n个数，你需要找到一个最长的子序列，使得这个子序列的第4k-4k+3项为a,b,a,b的形式(从0标号)。 牛逼的贪心啊，思维能力还是不行...... 思路倒是能想一点，但是代码写下来不行... 参考了 http://www.cnblogs.com/shiina-mashiro/p/3981944.html 思路： 1、处理四个数相等的情况，直接输出四个数就行----其中记录数出现的次数用map，这样就不用离散化了（网上查的说map的查询时logn，离散化...
Two polar bears Menshykov and Uslada from the St.Petersburg zoo and elephant Horace from the Kiev zoo got six sticks to play with and assess the animals' creativity. Menshykov, Uslada and Horace decided to make either an elephant or a bear from those sticks. They can make an animal from sticks in the following way: Four sticks represent the animals legs, these sticks should have the same length...
这次的CF除了最后一个都比较简单, 第一次用JAVA写CF....... Codeforces Round #269 (Div. 2) A. MUH and Sticks time limit per test 1 second memory limit per test 256 megabytes input standard input output ...