(Programme Language: C++) Find the last occurrence of the longest substring without repeating characters. You are asked to implement the function longestSubstring() as specified below. The drive program is to read the test cases from the input file and use them to test your implementation of longestSubstring(). HINS for longestSubstring(): Given a c-string str, find the last occurrence of the longest substring without repeating characters. Return a Substring object having the start position and the length of the longest substring. Precondition: the input string str is non-empty and contains ASCII characters only. Time Complexity Requirement: O(n) input.txt aaaa abababa abccba CP Pisfun theQUICKbrown FOXjumpsOVERtheLAZYdog Output: Case 1 The substring (3,1) is a Case 2 The substring (5,2) is ba Case 3 The substring (3,3) is cba Case 4 The substring (2,6) is Pisfun Case 5 The substring (0,21) is the QUICKbrown FOXjumps GIVEN CODES #include #include #include #include using namespace std; #define MAX_LENGTH 1000 // the max allowed input string length struct Substring // the structure used to store the function output int start; // the start position of the longest substring int length; // the length of the longest substring }; Substring longestSubstring(char*str) { ---FINISH THIS PART- int main(int argc, char** argv) { char str[MAX_LENGTH); // buffer ifstream fin("input.txt"); if (lfin) { cout > testcase; for (int i = 0; i > str; Substring longest = longestSubstring(str); cout