Codeforces 1105B：Zuhair and Strings（字符串水题）

最新推荐文章于 2019-08-16 14:55:27 发布

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最新推荐文章于 2019-08-16 14:55:27 发布

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分类专栏： Codeforces 字符串

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本文介绍了一种算法，用于在一个给定的字符串中查找连续出现k次的相同字符，且这些字符不能有重叠，旨在确定这种模式在字符串中最多出现的次数。通过实例解释了如何实现这一算法，并提供了一个简单的C++代码示例来解决这个问题。

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time limit per test: 1 second
memory limit per test: 256 megabytes
input: standard input
output: standard output

Given a string $s$ of length $n$ and integer $k\ (1≤k≤n)$ . The string $s$ has a level $x$ , if $x$ is largest non-negative integer, such that it’s possible to find in $s$ :

$x$ non-intersecting (non-overlapping) substrings of length $k$ ,
all characters of these x substrings are the same (i.e. each substring contains only one distinct character and this character is the same for all the substrings).

A substring is a sequence of consecutive (adjacent) characters, it is defined by two integers $i$ and $j\ (1≤i≤j≤n)$ , denoted as $s [i \dots j]$ = “ $s_is_{i+1}…s_j$ ”.

For example, if $k = 2$ , then:

the string “aabb” has level $1$ (you can select substring “aa”),
the strings “zzzz” and “zzbzz” has level $2$ (you can select two non-intersecting substrings “zz” in each of them),
the strings “abed” and “aca” have level $0$ (you can’t find at least one substring of the length $k = 2$ containing the only distinct character).
Zuhair gave you the integer $k$ and the string s of length $n$ . You need to find $x$ , the level of the string $s$ .

Input

The first line contains two integers $n$ and $k\ (1≤k≤n≤2⋅10^5)$ — the length of the string and the value of $k$ .

The second line contains the string $s$ of length n consisting only of lowercase Latin letters.

Output

Print a single integer $x$ — the level of the string.

Examples

input
8 2
aaacaabb
output
2
input
2 1
ab
output
1
input
4 2
abab
output
0

Note

In the first example, we can select $2$ non-intersecting substrings consisting of letter ‘a’: “(aa)ac(aa)bb”, so the level is $2$ .

In the second example, we can select either substring “a” or “b” to get the answer $1$ .

题意

给出一个长度为 $n$ 的字符串，在字符串中查找连续出现 $k$ 次的字母，中间不能有重叠，连续出现 $k$ 次的字母最多出现了几次

AC代码

暴力查找即可，注意 $k = 1$ 的情况

#include <stdio.h>
#include <string.h>
#include <iostream>
#include <algorithm>
#include <math.h>
#include <limits.h>
#include <map>
#include <stack>
#include <queue>
#include <vector>
#include <set>
#include <string>
#include <time.h>
#define ll long long
#define ull unsigned long long
#define ms(a,b) memset(a,b,sizeof(a))
#define pi acos(-1.0)
#define INF 0x7f7f7f7f
#define lson o<<1
#define rson o<<1|1
#define bug cout<<"-------------"<<endl
#define debug(...) cerr<<"["<<#__VA_ARGS__":"<<(__VA_ARGS__)<<"]"<<"\n"
const double E=exp(1);
const int maxn=1e6+10;
const int mod=1e9+7;
using namespace std;
char ch[maxn];
int a[maxn];
bool cmp(int a,int b)
{
	return a>b;
}
int main(int argc, char const *argv[])
{
	ios::sync_with_stdio(false);
	int n,k;
	cin>>n>>k;
	cin>>ch;
	int res=1;
	for(int i=0;i<n;i++)
	{
		if(k==1)
			a[ch[i]-'a']++;
		else
		{
			if(ch[i]==ch[i+1])
				res++;
			else
				res=1;	
			if(res==k)
			{
				a[ch[i]-'a']++;
				res=1;
				i+=1;
			}
		}
		
	}
	sort(a,a+26,cmp);
	cout<<a[0]<<endl;
	return 0;
}