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So there was this code which got accepted when i took its output in a vector

#include <iostream> #include<vector> using namespace std; int main(){ int t; cin >> t; while(t--){ vector<int>v; int n,k; cin >> n >> k; for(int i=0;i<n;i++){ int x; cin >> x; if(x%k==0) v.push_back(1); else v.push_back(0); } for(auto x:v) cout <<x <<""; cout << endl; } return 0; }

but then there is this code gives Time Limit Exceeded error when i am direct printing it

#include <bits/stdc++.h> using namespace std; #define ll long long int int main() { int t; cin>>t; while(t--) { ll k,d; int n,i; cin>>n>>k; for(i=0;i<n;i++) { cin>>d; if(d%k==0) cout<<"1"; else cout<<"0"; } cout<<"\n"; } }

Can you tell why ? (The contest is now over)Here is the question in case

Edit:1 I used int instead of long long as well as printf as well as cin.tie(NULL) stuff , but still to no avail

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    Console I/O is expensive. You should avoid putting it into busy loops if possible. I think that could be a huge performance hit. You're best off getting all input, processing, then printing all output in most cases since I/O in this case is probably your bottle-neck. Commented Jul 25, 2020 at 18:24
  • Probably irrelevant, but there are other difference in the code: you are using long long in the 2nd, and printing strings instead of ints. When comparing 2 pieces of code, try and remove all differences except what you're trying to compare. Commented Jul 25, 2020 at 18:28
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    ... and this is just the nth example of why if someone's goal is to learn C++, they won't learn anything from these worthless contests. In nearly all cases, like this one, the correct solution is requires knowledge of a particular programming trick. If you don't know what the trick is and attempt to code a brute-force approach, the program runs slow and fails for that reason. If you're trying to learn C++, you won't learn anything from meaningless online contest sites but only from a good C++ textbook. Commented Jul 25, 2020 at 18:32
  • @SamVarshavchik -- Unfortunately it seems that a lot of newbies are being absorbed into solving these questions because they have been told that they will get a lucrative job at a major software company if they can solve these questions and get some sort of "high rank" to show some recruiter.. That's the retort I seem to get when I ask them "what good are these tests?" That's probably also the reason why you see a lot of cries of desperation, and sometimes no effort in these questions -- gotta get those ranking points on the question site. Commented Jul 25, 2020 at 18:52
  • I don't know if it will provide a lucrative job or not but it definitely is a good practice ground for Google Code Jam or Kickstart or FB Hacker's cup Commented Jul 26, 2020 at 5:43

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The implementation with the cout in the for loop body is going to bottle-beck on the cout output for sure, especially given a modulo operation is very cheap in contrast.

See below question as reference:

C++: Does cout statement makes code slower

Something like this would work better:

#include <bits/stdc++.h> #include <vector> using namespace std; #define ll long long int int main() { int t; cin>>t; while(t--) { ll k,d; int n,i; cin>>n>>k; std::vector<bool> r(n); for(i=0;i<n;i++) { cin>>d; if(d%k==0) r[i] = true; } for(auto i : r) cout<<(i ? '1' : '0')<<endl; cout<<"\n"; } }
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