char* longestPalindrome(char* s) {

int slen = strlen(s);

int st = 0, ed = 0;

int ans = 1;

for(int i = 0 ; i < slen ; )

{

int j = i ;

int k = i ;

while( k+1 < slen && s[k] == s[k+1])k++;

i = k + 1;

while(k < slen-1 && j > 0 && s[k + 1] == s[j - 1])

{

k++; j--;

}

if(k-j + 1 > ans)

{

st = j;

ed = k;

ans = k-j+1;

}

}

s[ed+1] = 0;

return s+st;

}