Codeforces 676C Vasya and String (ruler)

The topic probably says to a string consisting of a and B, which can change up to K characters, and ask how long the longest consecutive and identical string can be obtained by changing it.

Use the ruler, change to a and change to B to do once: double pointer I and j,j non-stop +, and then if you encounter the need to change and change the number of times to let i++ correct the number of changes, and finally update the answer. Time complexity O (n).

Also, note the situation of the k=0.

1#include <cstdio>2#include <cstring>3#include <algorithm>4 using namespacestd;5 Charstr[111111];6 intMain () {7     intn,k;8scanf"%d%d%s",&n,&k,str);9     intI=0, j=0, tmpn=0, tmpk=0, ans=0;Ten      while(j<N) { One         if(str[j]=='a'){ A++TMPN; -}Else if(k==0){ -tmpn=0; the}Else{ -              while(tmpk==k) { -                 if(str[i]=='b'){ ---TMPK; +                 } ---TMPN; +++i; A             } at++TMPK; -++TMPN; -         } -ans=Max (ANS,TMPN); -++J; -     } inI=0; j=0; tmpn=0; tmpk=0; -      while(j<N) { to         if(str[j]=='b'){ +++TMPN; -}Else if(k==0){ thetmpn=0; *}Else{ $              while(tmpk==k) {Panax Notoginseng                 if(str[i]=='a'){ ---TMPK; the                 } +--TMPN; A++i; the             } +++TMPK; -++TMPN; $         } $ans=Max (ANS,TMPN); -++J; -     } theprintf"%d", ans); -     return 0;Wuyi}

Codeforces 676C Vasya and String (ruler)