codeforces #442 B

ACM_e發表於2017-10-24

B. Nikita and string
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

One day Nikita found the string containing letters "a" and "b" only.

Nikita thinks that string is beautiful if it can be cut into 3 strings (possibly empty) without changing the order of the letters, where the 1-st and the 3-rd one contain only letters "a" and the 2-nd contains only letters "b".

Nikita wants to make the string beautiful by removing some (possibly none) of its characters, but without changing their order. What is the maximum length of the string he can get?

Input

The first line contains a non-empty string of length not greater than 5 000 containing only lowercase English letters "a" and "b".

Output

Print a single integer — the maximum possible size of beautiful string Nikita can get.

Examples
input
abba
output
4
input
bab
output
2
Note

It the first sample the string is already beautiful.

In the second sample he needs to delete one of "b" to make it beautiful.


自己程式碼不忍直視 貼一個巨巨的  程式碼好強



#include<stdio.h>
#include<iostream>
#include<string>
#include<math.h>
using namespace std;
int max(int a,int b)
{
	return a>b?a:b;
}
int main()
{
    std::ios::sync_with_stdio(false);
        string s;
        cin>>s;
        int n=s.length(),i;
        int a=0,aba=0,ab=0;
        for(i=0;i<n;i++)
        {
            if(s[i]=='a') 
				aba++,a++;  //記錄總長度最長 和 a 的長度
            if(s[i]=='b')
				ab++;           //記錄  aaaa這樣的最長 還是  aaaaabbbb這種型別的 最長的長度
            aba=max(aba,ab);
            ab=max(ab,a);
        }
        cout<<aba;
    return 0;
}


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