I am solving a problem on SPOJ and am currently unsatisfied with my submission time, given that my fastest time is 0.28s (which ranks me 123/5037) and the leading submission is 0.04s.The problem is pretty simple: Given a list of bank account numbers, print the bank account number along with the frequency at which it is repeated.Inputt [the number of tests <= 5]  n [the number of accounts<= 100 000] [list of accounts]  [empty line]  [next test cases]Output[sorted list of accounts with the number of repeated accounts]  [empty line]  [other results]Example:Input:2603 10103538 2222 1233 6160 0142 03 10103538 2222 1233 6160 0141 30 10103538 2222 1233 6160 0141 30 10103538 2222 1233 6160 0142 30 10103538 2222 1233 6160 0141 30 10103538 2222 1233 6160 0142 530 10103538 2222 1233 6160 0144 30 10103538 2222 1233 6160 0142 30 10103538 2222 1233 6160 0145 30 10103538 2222 1233 6160 0146 30 10103538 2222 1233 6160 0143 Output:03 10103538 2222 1233 6160 0141 103 10103538 2222 1233 6160 0142 130 10103538 2222 1233 6160 0141 230 10103538 2222 1233 6160 0142 230 10103538 2222 1233 6160 0142 130 10103538 2222 1233 6160 0143 130 10103538 2222 1233 6160 0144 130 10103538 2222 1233 6160 0145 130 10103538 2222 1233 6160 0146 1In order to solve this, I am using a map where the key is the bank account and the value is the frequency of repetition. However, I am first loading the bank accounts into a vector, and I am pretty sure this is one area where I am losing efficiency. I have tried to avoid using the vector, but my efficiency is greatly reduced.What are some things that I can do to either improve my algorithm, or perhaps increase my I/O speed?#include <iostream>#include <map>#include <string>#include <vector>int main() {  std::ios_base::sync_with_stdio(false);  std::cin.tie(NULL);  int t;  std::cin >> t;  while (t--) {    int n, i;    std::cin >> n;    std::cin.ignore();    std::vector<std::string> accounts(n);    for (i = 0; i < n; ++i) {      std::getline(std::cin, accounts[i]);    }    std::cout << \n;    std::map<std::string, int> count;    for (i = 0; i < accounts.size(); ++i) {      auto map_it(count.find(accounts[i]));      if (map_it != count.end()) {        map_it->second++;      } else {        count[accounts[i]] = 1;      }    }    for (auto it = count.begin(); it != count.end(); ++it) {      std::cout << it->first << it->second << \n;    }    if (t != 0) {      std::string blank;      std::getline(std::cin, blank);    }  }  return 0;}
Counting the occurrences of bank account numbers for SPOJ challenge
c++;performance;programming challenge;hash map