Hello Coders,↵
Suppose I have string s and I'm creating new string s1 by s1=s[j--]+s1 where j is initially (j=s.length()-1).↵
Is this operation in C++ is time costly.↵
↵
Because I was solving [D2. Prefix-Suffix Palindrome (Hard version)↵
](https://codeforces.net/contest/1326/problem/D2) problem.In this problem we are given string s,and we need to find ↵
string t,which satisfy given condition.↵
↵
1)The length of t does not exceed the length of s.↵
↵
2)t is a palindrome.↵
↵
3)There exists two strings a and b (possibly empty), such that t=a+b ( "+" represents concatenation), and a is prefix of s while b is suffix of s.↵
↵
I tried to solve it in following way,↵
↵
1)string s1=s2="" and i=0,j=s.length()-1, now till s[i]==s[j],I added elements to s1 and s2;↵
ie. s1+=s[i++],s2=s[j--]+s2;↵
↵
2)after first step whatever string remains unused,I found longest prefix and suffix palindrome using manachers alg,and choosen ↵
max of them.↵
↵
Now Main point is that when I submitted it was giving TLE on testcase 13.↵
then I just tried to change s2=s[j--]+s2 by just only finding s1 and s2 will be obviously reverse of s1.↵
And my code gets Accepted.↵
↵
So my question is how can s2=s[j--]+s2 can be reason for TLE?↵
↵
[sol having TLE](https://codeforces.net/contest/1326/submission/85893140).↵
↵
[Accepted sol](https://codeforces.net/contest/1326/submission/85893300).↵
↵
Both sols only differ in way I calculated s2.↵
↵
UP1: I don't know what's wrong with some people, I have seen many comments in announcement or in tutorial section that's↵
are either funny or sarcastic or memes ,and they gets many upvotes,I'm not saying that should not be upvoted,in fact If ↵
I like,I also upvotes them.But when some one ask for doubt most of the time it gets downvoted. IDK why?↵
↵
I think many people started taking it in wrong way, they think that If they didn't like post or comment then it should be↵
downvoted.But what is meaning of contribution? If someone if contributing to community then he should get +ve contribution↵
and If he is spreading negativity,he should be downvoted.↵
↵
But when someone ask doubt then surely he is not harming community, also he is not contributing to community either because↵
he asked doubt for himself and it may not be useful to all people.So when someone ask doubt,two things possible ↵
either his doubts may not be useful to someone or someone having similar doubt can solve it by reading comments by others.↵
Then how it is harming community that many are downvoting. If they thinks it is not useful they can just ignore it,what's↵
reason for downvote.↵
↵
I just tried to said what I felt after seeing downvotes on my this blog and others blogs asking for doubts,May be I will be ↵
downvoted for saying this.
Suppose I have string s and I'm creating new string s1 by s1=s[j--]+s1 where j is initially (j=s.length()-1).↵
Is this operation in C++ is time costly.↵
↵
Because I was solving [D2. Prefix-Suffix Palindrome (Hard version)↵
](https://codeforces.net/contest/1326/problem/D2) problem.In this problem we are given string s,and we need to find ↵
string t,which satisfy given condition.↵
↵
1)The length of t does not exceed the length of s.↵
↵
2)t is a palindrome.↵
↵
3)There exists two strings a and b (possibly empty), such that t=a+b ( "+" represents concatenation), and a is prefix of s while b is suffix of s.↵
↵
I tried to solve it in following way,↵
↵
1)string s1=s2="" and i=0,j=s.length()-1, now till s[i]==s[j],I added elements to s1 and s2;↵
ie. s1+=s[i++],s2=s[j--]+s2;↵
↵
2)after first step whatever string remains unused,I found longest prefix and suffix palindrome using manachers alg,and choosen ↵
max of them.↵
↵
Now Main point is that when I submitted it was giving TLE on testcase 13.↵
then I just tried to change s2=s[j--]+s2 by just only finding s1 and s2 will be obviously reverse of s1.↵
And my code gets Accepted.↵
↵
So my question is how can s2=s[j--]+s2 can be reason for TLE?↵
↵
[sol having TLE](https://codeforces.net/contest/1326/submission/85893140).↵
↵
[Accepted sol](https://codeforces.net/contest/1326/submission/85893300).↵
↵
Both sols only differ in way I calculated s2.↵
↵
UP1: I don't know what's wrong with some people, I have seen many comments in announcement or in tutorial section that's↵
are either funny or sarcastic or memes ,and they gets many upvotes,I'm not saying that should not be upvoted,in fact If ↵
I like,I also upvotes them.But when some one ask for doubt most of the time it gets downvoted. IDK why?↵
↵
I think many people started taking it in wrong way, they think that If they didn't like post or comment then it should be↵
downvoted.But what is meaning of contribution? If someone if contributing to community then he should get +ve contribution↵
and If he is spreading negativity,he should be downvoted.↵
↵
But when someone ask doubt then surely he is not harming community, also he is not contributing to community either because↵
he asked doubt for himself and it may not be useful to all people.So when someone ask doubt,two things possible ↵
either his doubts may not be useful to someone or someone having similar doubt can solve it by reading comments by others.↵
Then how it is harming community that many are downvoting. If they thinks it is not useful they can just ignore it,what's↵
reason for downvote.↵
↵
I just tried to said what I felt after seeing downvotes on my this blog and others blogs asking for doubts,May be I will be ↵
downvoted for saying this.
