Codeforces Round #418 (Div. 2).C two points
2 seconds
256 megabytes
standard input
standard output
Nadeko's birthday is approaching! As she decorated the room for the party, a long garland of Dianthus-shaped paper pieces was placed on a prominent part of the wall. Brother Koyomi will like it!
Still unsatisfied with the garland, Nadeko decided to polish it again. The garland has n pieces numbered from 1 to n from left to right, and the i-th piece has a colour si, denoted by a lowercase English letter. Nadeko will repaint at most m of the pieces to give each of them an arbitrary new colour (still denoted by a lowercase English letter). After this work, she finds out all subsegments of the garland containing pieces of only colour c — Brother Koyomi's favourite one, and takes the length of the longest among them to be the Koyomity of the garland.
For instance, let's say the garland is represented by "kooomo", and Brother Koyomi's favourite colour is "o". Among all subsegments containing pieces of "o" only, "ooo" is the longest, with a length of 3. Thus the Koyomity of this garland equals 3.
But problem arises as Nadeko is unsure about Brother Koyomi's favourite colour, and has swaying ideas on the amount of work to do. She has q plans on this, each of which can be expressed as a pair of an integer mi and a lowercase letter ci, meanings of which are explained above. You are to find out the maximum Koyomity achievable after repainting the garland according to each plan.
The first line of input contains a positive integer n (1 ≤ n ≤ 1 500) — the length of the garland.
The second line contains n lowercase English letters s1s2... sn as a string — the initial colours of paper pieces on the garland.
The third line contains a positive integer q (1 ≤ q ≤ 200 000) — the number of plans Nadeko has.
The next q lines describe one plan each: the i-th among them contains an integer mi (1 ≤ mi ≤ n) — the maximum amount of pieces to repaint, followed by a space, then by a lowercase English letter ci — Koyomi's possible favourite colour.
Output q lines: for each work plan, output one line containing an integer — the largest Koyomity achievable after repainting the garland according to it.
6
koyomi
3
1 o
4 o
4 m
3
6
5
15
yamatonadeshiko
10
1 a
2 a
3 a
4 a
5 a
1 b
2 b
3 b
4 b
5 b
3
4
5
7
8
1
2
3
4
5
10
aaaaaaaaaa
2
10 b
10 z
10
10
In the first sample, there are three plans:
- In the first plan, at most 1 piece can be repainted. Repainting the "y" piece to become "o" results in "kooomi", whose Koyomity of 3is the best achievable;
- In the second plan, at most 4 pieces can be repainted, and "oooooo" results in a Koyomity of 6;
- In the third plan, at most 4 pieces can be repainted, and "mmmmmi" and "kmmmmm" both result in a Koyomity of 5.
思路:尺取法。
代码:
#include "cstdio"
#include "iostream"
#include "algorithm"
#include "string"
#include "cstring"
#include "queue"
#include "cmath"
#include "vector"
#include "map"
#include "stdlib.h"
#include "set"
#define mj
#define db double
#define ll long long
using namespace std;
;
;
;
char s[N];
int x,n,m;
char e;
void f(char e){
,r=,cnt=,res=;
while(l<n&&r<n){//限制条件
while ((cnt<x||s[r]==e)&&r<n){
if(s[r++]!=e) cnt++;//统计目标字母的个数
}
res=max(res,r-l);
if(cnt<x) break;
while(s[l]==e&&l<=r) l++;
cnt--,l++;
}
printf("%d\n",res);
}
int main()
{
scanf("%d",&n);
scanf("%s",s);
scanf("%d",&m);
;i<m;i++){
scanf("%d %c",&x,&e);
f(e);
}
;
}
Codeforces Round #418 (Div. 2).C two points的更多相关文章
- Codeforces Round #418 (Div. 2) D. An overnight dance in discotheque
Codeforces Round #418 (Div. 2) D. An overnight dance in discotheque 题意: 给\(n(n <= 1000)\)个圆,圆与圆之间 ...
- Codeforces Round #594 (Div. 2) A. Integer Points 水题
A. Integer Points DLS and JLS are bored with a Math lesson. In order to entertain themselves, DLS to ...
- Codeforces Round #455 (Div. 2) 909D. Colorful Points
题 OvO http://codeforces.com/contest/909/problem/D CF 455 div2 D CF 909D 解 算出模拟的复杂度之后就是一个很水的模拟题 把字符串按 ...
- Codeforces Round #624 (Div. 3) F. Moving Points 题解
第一次写博客 ,请多指教! 翻了翻前面的题解发现都是用树状数组来做,这里更新一个 线段树+离散化的做法: 其实这道题是没有必要用线段树的,树状数组就能够解决.但是个人感觉把线段树用熟了会比树状数组更有 ...
- Codeforces Round #230 (Div. 2) C Blocked Points
题目链接 题意 : 给你一个半径为n的圆,圆里边还有圆上都有很多整点,让你找出与圆外的任意一个整点距离等于1的点. 思路 :这个题可以用枚举,画个图就发现了,比如说先数第一象限的,往下往右找,还可以找 ...
- Codeforces Round #418 (Div. 2)
A: 不细心WA了好多次 题意:给你一个a序列,再给你个b序列,你需要用b序列中的数字去替换a序列中的0,如果能够替换,则需要判断a是否能构成一个非递增的序列,a,b中所有的数字不会重复 思路:就是一 ...
- Codeforces Round #418 (Div. 2) B. An express train to reveries
time limit per test 1 second memory limit per test 256 megabytes input standard input output standar ...
- Codeforces Round #418 (Div. 2)D
给n个圆要么包含,要么相分离,没有两个公共点,当成一棵树,把包含的面积大的放在上面 如图最上面的par记为-1,level记为0,当par==-1||level==1时就加否则减, 就是第一,二层先加 ...
- Codeforces Round #418 (Div. 2) A+B+C!
终判才知道自己失了智.本场据说是chinese专场,可是请允许我吐槽一下题意! A. An abandoned sentiment from past shabi贪心手残for循环边界写错了竟然还过了 ...
随机推荐
- Java基础知识二次学习-- 第一章 java基础
基础知识有时候感觉时间长似乎有点生疏,正好这几天有时间有机会,就决定重新做一轮二次学习,挑重避轻 回过头来重新整理基础知识,能收获到之前不少遗漏的,所以这一次就称作查漏补缺吧!废话不多说,开始! 第一 ...
- 无锁模式的Vector
这两天学习无锁的并发模式,发现相比于传统的 同步加锁相比,有两点好处1.无锁 模式 相比于 传统的 同步加锁 提高了性能 2.无锁模式 是天然的死锁免疫 下来介绍无锁的Vector--- LockF ...
- .net实现多重继承问题(virtual)
C#中是没有类的多重继承这个概念.要使用多重继承必须要通过接口Interface来完成, 一.接口类 interface getTable{ DataTable Getdatatable( ...
- java中文件操作《一》
在日常的开发中我们经常会碰到对文件的操作,在java中对文件的操作都在java.io包下,这个包下的类有File.inputStream.outputStream.FileInputStream.Fi ...
- Python多线程和多进程谁更快?
python多进程和多线程谁更快 python3.6 threading和multiprocessing 四核+三星250G-850-SSD 自从用多进程和多线程进行编程,一致没搞懂到底谁更快.网上很 ...
- mongoose populate
mongoose具备关系数据库一样的关联查询,通过在schema模型中设置ref属性,然后在查询时使用populate关键字,可以达到关联查询的目的. 以下内容参考了mongoose官方文档http: ...
- java实现文件批量导入导出实例(兼容xls,xlsx)
1.介绍 java实现文件的导入导出数据库,目前在大部分系统中是比较常见的功能了,今天写个小demo来理解其原理,没接触过的同学也可以看看参考下. 目前我所接触过的导入导出技术主要有POI和iRepo ...
- Maximum Subarray Sum
Maximum Subarray Sum 题意 给你一个大小为N的数组和另外一个整数M.你的目标是找到每个子数组的和对M取余数的最大值.子数组是指原数组的任意连续元素的子集. 分析 参考 求出前缀和, ...
- Spring Task每次都会调用两次的问题
最近一个Spring Mvc的项目中需要定时执行一个任务,所以使用了spring 自带的Task功能.本地调试的时候一切都正常,可是部署到服务器上后,每次任务都会被调用两次.在网上搜索了相关的问题,排 ...
- java map集合的知识
/** * Map用于存储键值对,不允许键重复,值可以重复. * (1)HashMap是一个最常用的Map,它根据键的hashCode值存储数据,根据键可以直接获取它的值,具有很快的访问速度. * H ...