{HELP} - What's wrong in this code for THE NEXT PALINDROME problem?

help
, , ,
1

THANKS IN ADVANCE !!!

//JUST LIKE ANIMALS !!!!

#include<bits/stdc++.h>
using namespace std;
typedef unsigned long long ll;

bool ispalin(ll n){
ll i;
string s=to_string(n);
for(i=0;i<(s.length()/2);i++){
	if(s[i]!=s[s.length()-1-i]){
		return false;
	}
}
return true;

}

int main(){
int t;cin>>t;
while(t--){
	ll n,i;cin>>n;
	if(n<10)cout<<n+1<<endl;
	else
	if(n%99==0&&n%11==0)cout<<n+2<<endl;
	else{
		for(i=n+1;;i++){
		if(ispalin(i)==true)
		{
			cout<<i<<endl;break;
		}
	}
	}
}
return 0;

}

2

The mistake which I can see is that, for the test case :-
1
5

It gives the output as 11, but the output should be 6, because single digit numbers are by default palindrome.

3

Corrected it , still WA

4

You should link the problem url? Since i have done similar problem in the past, i would assume it is http://www.spoj.com/problems/PALIN/
Note this line which says “positive integer K of not more than 1000000 digits”, you simply cannot take the input to an integer. Do it as a string problem

1 Like
5

Your second condition is wrong,for inputs like 9900 it will not give correct answer it gives 9902 but which is not correct. I think this makes you clear what is the mistake in your code

1 Like
6

Can anybody help me

NZEC is coming for The Next Palindrome

import java.util.*;
class Main
{

	public static boolean palin(long a){
		long right=a;
		long rev=0;
		while(a>=10){
			rev=rev*10+a%10;
			a=a/10;
			
		}
		rev=rev*10+a;
		if(rev==right)
		    return true;
		 else
		     return false;
	}



public static void main (String[] args) throws java.lang.Exception
{
  Scanner scan=new Scanner(System.in);
	int turn=scan.nextInt();
	for(int i=0;i<turn;i++){
	long num=scan.nextLong();	
	 while(palin(++num)!=true){
		 }
	 System.out.println(num);
}

}
}

7

Please someone help.
I don’t know why it is giving wrong answer. i tried it with many test cases but i still can’t point out the issue. Problem iink and my solution link are:
https://www.codechef.com/problems/PALIN
https://www.codechef.com/viewsolution/14249426