Codeforces 526.D Om Nom and Necklace
1 second
256 megabytes
standard input
standard output
One day Om Nom found a thread with n beads of different colors. He decided to cut the first several beads from this thread to make a bead necklace and present it to his girlfriend Om Nelly.

Om Nom knows that his girlfriend loves beautiful patterns. That's why he wants the beads on the necklace to form a regular pattern. A sequence of beads S is regular if it can be represented as S = A + B + A + B + A + ... + A + B + A, where A and B are some bead sequences, " + " is the concatenation of sequences, there are exactly 2k + 1 summands in this sum, among which there are k + 1 "A" summands and k "B" summands that follow in alternating order. Om Nelly knows that her friend is an eager mathematician, so she doesn't mind if A or B is an empty sequence.
Help Om Nom determine in which ways he can cut off the first several beads from the found thread (at least one; probably, all) so that they form a regular pattern. When Om Nom cuts off the beads, he doesn't change their order.
The first line contains two integers n, k (1 ≤ n, k ≤ 1 000 000) — the number of beads on the thread that Om Nom found and number kfrom the definition of the regular sequence above.
The second line contains the sequence of n lowercase Latin letters that represent the colors of the beads. Each color corresponds to a single letter.
Print a string consisting of n zeroes and ones. Position i (1 ≤ i ≤ n) must contain either number one if the first i beads on the thread form a regular sequence, or a zero otherwise.
7 2
bcabcab
0000011
21 2
ababaababaababaababaa
000110000111111000011
In the first sample test a regular sequence is both a sequence of the first 6 beads (we can take A = "", B = "bca"), and a sequence of the first 7 beads (we can take A = "b", B = "ca").
In the second sample test, for example, a sequence of the first 13 beads is regular, if we take A = "aba", B = "ba".
大致题意:给一个字符串,问该字符串的[1,i]位上的字符串能不能由A+B+A+B+......+A构成?其中k+1个A,k个B,A,B可以为空串.
分析:分别枚举A,B不大好做,但是AB可以拼起来,原题就变成了能不能用k个AB和1个A拼成,AB作为一个循环节,要先求循环节的长度,利用kmp的next数组得到.最小循环节的t倍还是循环节,记作cir,那么问题就是判断能否存在t使得i / (t * cir) = k或i = (k+1) * t*cir
(A是空串).这个问题就比较简单了,将t用i,cir,k表示,检验t是否>0并且满足条件式子.
#include <cstdio>
#include <cstring>
#include <iostream>
#include <algorithm> using namespace std; int n, k, nextt[];
char s[]; void init()
{
int j = ;
for (int i = ; i <= n; i++)
{
while (j > && s[j + ] != s[i])
j = nextt[j];
if (s[j + ] == s[i])
j++;
nextt[i] = j;
}
} bool check(int x)
{
int cir = x - nextt[x];
if (x % (k + ) == && (x / (k + )) % cir == )
return true;
int t = x / (k * cir);
if (t > && x / (cir * t) == k)
return true;
return false;
} int main()
{
scanf("%d%d", &n, &k);
scanf("%s", s + );
init();
for (int i = ; i <= n; i++)
{
if (check(i))
printf("");
else
printf("");
} return ;
}
Codeforces 526.D Om Nom and Necklace的更多相关文章
- 【Codeforces 526D】Om Nom and Necklace
Codeforces 526 D 题意:给一个字符串,求每个前缀是否能表示成\(A+B+A+B+\dots+A\)(\(k\)个\(A+B\))的形式. 思路1:求出所有前缀的哈希值,以便求每个子串的 ...
- Codeforces 526D - Om Nom and Necklace 【KMP】
ZeptoLab Code Rush 2015 D. Om Nom and Necklace [题意] 给出一个字符串s,判断其各个前缀是否是 ABABA…ABA的形式(A和B都可以为空,且A有Q+1 ...
- Codeforces - ZeptoLab Code Rush 2015 - D. Om Nom and Necklace:字符串
D. Om Nom and Necklace time limit per test 1 second memory limit per test 256 megabytes input standa ...
- Codeforces 526D Om Nom and Necklace (KMP)
http://codeforces.com/problemset/problem/526/D 题意 给定一个串 T,对它的每一个前缀能否写成 A+B+A+B+...+B+A+B+A+B+...+B+A ...
- CodeForces 526D Om Nom and Necklace
洛谷题目页面传送门 & CodeForces题目页面传送门 给定字符串\(a\),求它的每一个前缀,是否能被表示成\(m+1\)个字符串\(A\)和\(m\)个字符串\(B\)交错相连的形式, ...
- Codeforces ZeptoLab Code Rush 2015 D.Om Nom and Necklace(kmp)
题目描述: 有一天,欧姆诺姆发现了一串长度为n的宝石串,上面有五颜六色的宝石.他决定摘取前面若干个宝石来做成一个漂亮的项链. 他对漂亮的项链是这样定义的,现在有一条项链S,当S=A+B+A+B+A+. ...
- CF526D Om Nom and Necklace
嘟嘟嘟 我们可以把AB看成S,则要找的串可以写成SSSSA或者SSSSS.假设S出现了Q次,那么A出现了Q % k次,则B出现了 Q / k - Q % k次. 当ABABA是SSS的形式时,B可以为 ...
- 【Henu ACM Round#16 F】Om Nom and Necklace
[链接] 我是链接,点我呀:) [题意] 在这里输入题意 [题解] KMP算法可以把"i前缀"pre[i] 分成ssssst的形式 这里t是s的前缀. 然后s其实就是pre[i]中 ...
- Codeforces C - Om Nom and Candies
C - Om Nom and Candies 思路:贪心+思维(或者叫数学).假设最大值max(wr,wb)为wr,当c/wr小于√c时,可以枚举r糖的数量(从0到c/wr),更新答案,复杂度√c:否 ...
随机推荐
- MySQL事务、并发问题、锁机制
MySQL事务,并发问题,锁机制 1.什么是事务 事务是一条或多条数据库操作语句的组合,具备ACID,4个特点. 原子性:要不全部成功,要不全部撤销 隔离性:事务之间相互独立,互不干扰 一致性:数据库 ...
- [network]RIP协议
水平分割:一种避免路由环路的出现和加快路由汇聚的技术. 原理:路由器从某个接口接收到的更新信息不允许再从这个接口发送回去. 优点:1. 阻止路由环路产生:2. 减少路由器更新信息占用的链路带宽资源. ...
- 好用的MarkDown编辑器
MarkDown是编写文档非常有用的一个好工具
- 基于zookeeper+mesos+marathon的docker集群管理平台
参考文档: mesos:http://mesos.apache.org/ mesosphere社区版:https://github.com/mesosphere/open-docs mesospher ...
- 华为笔试——C++的int型数字位排序
题目:int型数字位排序 题目介绍:输入int 型整数,按照从右至左的顺序,返回不含重复数字的新整数. 例: 输入: 99824270 输出: 072489 分析:乍一看很简单,但是很容易忽略int ...
- springjdbc使用c3p0连接池报错 java.lang.NoClassDefFoundError: com/mchange/v2/ser/Indirector
MyMaincom.test.sunc.MyMaintestMethod(com.test.sunc.MyMain)org.springframework.beans.factory.BeanCrea ...
- Python最简编码规范
前言 本文是阅读<Python Coding Rule>之后总结的最为精华及简单的编码规范,根据每个人不同喜好有些地方会有不同的选择,我只是做了对自己来说最简单易行的选择,仅供大家参考. ...
- c++ Dynamic Memory (part 2)
Don't use get to initialize or assign another smart pointer. The code that use the return from get c ...
- ES6的新特性(21)——Proxy
Proxy 概述 Proxy 用于修改某些操作的默认行为,等同于在语言层面做出修改,所以属于一种“元编程”(meta programming),即对编程语言进行编程. Proxy 可以理解成,在目标对 ...
- Scrum立会报告+燃尽图(十一月二十日总第二十八次):功能开发与纪录版本控制报告
此作业要求参见:https://edu.cnblogs.com/campus/nenu/2018fall/homework/2284 项目地址:https://git.coding.net/zhang ...