Codeforces Round #354 (Div. 2) C (二分???)
2016-05-26 23:08
405 查看
C. Vasya and String
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
High school student Vasya got a string of length n as a birthday present. This string consists of letters 'a'
and 'b' only. Vasya denotesbeauty of the string as the maximum length of a substring (consecutive
subsequence) consisting of equal letters.
Vasya can change no more than k characters of the original string. What is the maximum beauty of the string he can achieve?
Input
The first line of the input contains two integers n and k (1 ≤ n ≤ 100 000, 0 ≤ k ≤ n) —
the length of the string and the maximum number of characters to change.
The second line contains the string, consisting of letters 'a' and 'b'
only.
Output
Print the only integer — the maximum beauty of the string Vasya can achieve by changing no more than k characters.
Examples
input
output
input
output
Note
In the first sample, Vasya can obtain both strings "aaaa" and "bbbb".
In the second sample, the optimal answer is obtained with the string "aaaaabaa" or with the string "aabaaaaa".
题解:
有一个长度为n的字符串,这个字符串只含有a和b,你可以改变最多k次,问你连续最长的一样的字符串是多长?
从头到尾都遍历-->枚举-->改变 ,贪心最长度。 有点像二分
AC代码:
#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int n,k;
int f(string s)
{
int l=0,r=-1;
int num=0;
int res=0;
while(++r<s.size())
{
if(s[r]=='b')
num++;
if(num>k)
{
while(s[l++]=='a');
num--;
}
res=max(res,r-l+1);
}
return res;
}
int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
string s;
cin>>n>>k;
cin>>s;
int ans=f(s);
for(int i=0;i<s.size();i++)
s[i]='a'+'b'-s[i];
ans=max(ans,f(s));
cout<<ans<<endl;
return 0;
}
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
High school student Vasya got a string of length n as a birthday present. This string consists of letters 'a'
and 'b' only. Vasya denotesbeauty of the string as the maximum length of a substring (consecutive
subsequence) consisting of equal letters.
Vasya can change no more than k characters of the original string. What is the maximum beauty of the string he can achieve?
Input
The first line of the input contains two integers n and k (1 ≤ n ≤ 100 000, 0 ≤ k ≤ n) —
the length of the string and the maximum number of characters to change.
The second line contains the string, consisting of letters 'a' and 'b'
only.
Output
Print the only integer — the maximum beauty of the string Vasya can achieve by changing no more than k characters.
Examples
input
4 2 abba
output
4
input
8 1 aabaabaa
output
5
Note
In the first sample, Vasya can obtain both strings "aaaa" and "bbbb".
In the second sample, the optimal answer is obtained with the string "aaaaabaa" or with the string "aabaaaaa".
题解:
有一个长度为n的字符串,这个字符串只含有a和b,你可以改变最多k次,问你连续最长的一样的字符串是多长?
从头到尾都遍历-->枚举-->改变 ,贪心最长度。 有点像二分
AC代码:
#include<bits/stdc++.h>
using namespace std;
const int N = 1e5+10;
int n,k;
int f(string s)
{
int l=0,r=-1;
int num=0;
int res=0;
while(++r<s.size())
{
if(s[r]=='b')
num++;
if(num>k)
{
while(s[l++]=='a');
num--;
}
res=max(res,r-l+1);
}
return res;
}
int main()
{
//freopen("in.txt","r",stdin);
//freopen("out.txt","w",stdout);
string s;
cin>>n>>k;
cin>>s;
int ans=f(s);
for(int i=0;i<s.size();i++)
s[i]='a'+'b'-s[i];
ans=max(ans,f(s));
cout<<ans<<endl;
return 0;
}
相关文章推荐
- DirectFB 之 通过多Window实现多元素处理
- 获取屏幕像素
- mysql字符集相关 Illegal mix of collations (gbk_chinese_***) and (gb2312_chinese_***) for operation '
- DirectFB 之 通过多Window实现多元素处理
- 使8253输出1S的方波,使通道外接的发光二极管亮1S,暗1S
- 3、Spring的AOP详解和案例
- 函数匹配
- 自定义控件
- 多态and接口
- LeetCode 106. Construct Binary Tree from Inorder and Postorder Traversal
- 6.2、临时表--Oracle模式对象
- thinkphp 3.2.3 计划任务具体实现实例教程
- 【android】:method(Bundle) onCreate is undefined
- //求某一确定数组的最大值、和。
- HBITMAP与BITMAP 的区别
- MDL最小描述长度在分词研究中的应用
- Java EE开发平台随手记1
- 161_界面颜色亮度属性变化
- Important Concepts in Virtual Reality Course
- 《挪威的森林》进行时