cf 1216a

Posted 2020-11-16 zjxxcn

https://codeforc.es/problemset/problem/1216/A

 

本题直接$O(n)$贪心。 

 1 #include<bits/stdc++.h>
 2 using namespace std;  
 3 int const N=200000+10;  
 4 char s[N];    
 5 int main(){
 6     int n,ans=0,num=0;   
 7     scanf("%d%s",&n,s+1);  
 8     for(int i=1;i<=n;i++){
 9         if(i&1) num+=s[i]==‘a‘;  
10         else {
11             num+=s[i]==‘a‘;  
12             if(num==0)
13                 s[i]=‘a‘,ans++;    
14             else if(num==2)
15                 s[i]=‘b‘,ans++;  
16             num=0;   
17         }
18     }
19     printf("%d
",ans);  
20     printf("%s",s+1); 
21     return 0; 
22 }

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