#include <iostream> #include <vector> using namespace std; class HashTables{ public: static const int TableSize = 10; int Table[TableSize]; HashTables() { for(int i = 0; i < TableSize; i ++) { Table[i] = 0; } } void recurring(vector<int> arr) { int i; for(i = 0 ; i < arr.size(); i ++) { if(Table[arr[i]] == 1){ cout << arr[i]; return; } if(Table[arr[i]] < 2) Table[arr[i]]++; } if(i == arr.size()){ cout << "undefined"; } } }; int main() { vector<int> One = {2,5,1,2,3,5,1,2,4}; vector<int> Two = {2,1,1,2,1,3,5,1,2,4}; vector<int> Three = {2,3,4,5}; HashTables Find; Find.recurring(Three); return 0; }