<prompt> Kuandika kazi c kutatua: Kutokana na kamba s ambayo ina herufi ndogo au kubwa, kurudi urefu wa palindrome ndefu ambayo inaweza kujengwa na herufi hizo. herufi ni kesi nyeti, kwa mfano, Aa si kuchukuliwa palindrome hapa.  <response>: Heres a possible C solution to solve this problem:int longestPalindromestring s int freq52 0; frequency of each letter lowercase and uppercase forchar c : s ifc a c z freqc - a; lowercase letter else freqc - A 26; uppercase letter bool oddFound false; whether an odd frequency letter has been found int length 0; length of the longest palindrome forint i 0; i 52; i iffreqi 2 0 length freqi; even frequency letter use all else odd frequency letter use all but one length freqi - 1; if!oddFound use the first odd frequency letter found length; add one to the length oddFound true; mark as used return length;The approach is to count the frequency of each letter both lowercase and uppercase, and then iterate over them to build the longest palindrome possible. For each letter frequency, if its even, we can use all occurrences of that letter in the palindrome. If its odd, we can use all but one occurrence, and we need to keep track of whether we have found an odd frequency letter already, so that we only use one.The time complexity of this algorithm is On, where n is the length of the input string. 