#include #include #include #include #include #define pr pair using namespace std; int main() { srand(time(0)); auto longestPalindrome=[](string s) { //stores character occurence map occurs; vector v; // stores the final output // allow only once for maps having value 1 int i=0, onlyOnce=false; do { int cnt=count(begin(s), end(s), s[i]); if (cnt==1 && onlyOnce==false) { occurs.insert(make_pair(s[i], cnt)); onlyOnce=true; } else if(cnt>1) occurs.insert(make_pair(s[i], cnt)); i++; } while (i<(int)s.length()); // sorting the map value base on occurence vector vec; copy(occurs.begin(), occurs.end(), back_inserter < vector>(vec)); sort(vec.begin(), vec.end(), [](const pr& l, const pr& r) { if (l.second!=r.second) return l.secondsecond&1 && flag) { for (int j=0; jsecond; j++) v.push_back(i->first); flag = !flag; } else { for (int j=0; jsecond/2; j++){ v.insert(v.begin(), i->first); v.insert(v.end(), i->first); } } } // checks palindrome or not and then prints while (!(equal(v.begin(), v.begin()+v.size()/2, v.rbegin()))){ random_shuffle(begin(v), end(v)); random_shuffle(begin(v), end(v)); } for (size_t i=0; i> in; vector tc{ in, "beginning", "solutomaattimittaamotulosr", "kinnikinnik","equilibrium", "classmate", "mmadam", "babab", "abbabab", "abdccdceeebebc", "hello", "longestpalindrome" }; for (auto s : tc) cout< ", longestPalindrome(s); } /* Longest palindrome problem find the longest palindrome string from the given string. Example Input : bababb Output : bbaabb Input : abbabab Output : bbaaabb Input : abdccdceeebebc Output : eedccbabccdee Created for this challenge: https://www.sololearn.com/post/392555 */