Language: C++

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

#define Unknown ios_base::sync_with_stdio(0);ios::sync_with_stdio(0);cin.tie(nullptr);cout.tie(nullptr);
#define percision(x)     cout << fixed << setprecision(x);
#define nl '\n'

#define fo(i, a, n) for(int i{ (int) (a) };i < (int)(n);i++)
#define fr(i, a, n) for(int i{ (int) (a) };i <= (int)(n);i++)
#define frr(i, a, n) for(int i{ (int) (a) };i > (int) (n);i--)
#define frrr(i, a, n) for(int i{ (int) (a) };i >= (int) (n);i--)
#define trav(i, x) for(auto &i : x)

#define mp make_pair
#define eb emplace_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound
#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)

typedef long long ll;
typedef long double ld;
typedef unsigned long long ull;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;
typedef pair<ull, ull> pul;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;
typedef vector<pul> vpul;

const double PI = 2 * acos(0.0);
const double EPS = (1e-10);
const double inf = 1.0/0.0;
const int OO = 0x3f3f3f3f;
const int N = 1e5 + 20;
const int MOD = (int)(1e9) + 7;/// 998244353
int dx8[8] = {0, 1, 1, 1, 0, -1, -1, -1};int dy8[8] = {1, 1, 0, -1, -1, -1, 0, 1}; ///8 Direction
int dx4[4] = {1, 0, -1, 0};int dy4[4] = {0, 1, 0, -1}; ///4 Direction

template<class... T> inline re(T&... args) { ((cin >> args), ...); }
template<class T> inline cmin(T &a, T b) { a = min(a, b); }
template<class T> inline cmax(T &a, T b) { a = max(a, b); }

int main(){
    Unknown
    int n{}, l{};
    re(n, l);
    string str[n], tmp{};

    fo(i, 0, n){
        re(str[i]);
    }

    sort(str, str + n);

    fo(i, 0, n){
        tmp += str[i];
    }

    cout << tmp;

    return 0;
}


Compiler output:
a.cc:57:29: error: ISO C++ forbids declaration of 're' with no type [-fpermissive]
   57 | template<class... T> inline re(T&... args) { ((cin >> args), ...); }
      |                             ^~
a.cc: In function 'int re(T& ...)':
a.cc:57:68: warning: no return statement in function returning non-void [-Wreturn-type]
   57 | template<class... T> inline re(T&... args) { ((cin >> args), ...); }
      |                                                                    ^
a.cc: At global scope:
a.cc:58:26: error: ISO C++ forbids declaration of 'cmin' with no type [-fpermissive]
   58 | template<class T> inline cmin(T &a, T b) { a = min(a, b); }
      |                          ^~~~
a.cc: In function 'int cmin(T&, T)':
a.cc:58:59: warning: no return statement in function returning non-void [-Wreturn-type]
   58 | template<class T> inline cmin(T &a, T b) { a = min(a, b); }
      |                                                           ^
a.cc: At global scope:
a.cc:59:26: error: ISO C++ forbids declaration of 'cmax' with no type [-fpermissive]
   59 | template<class T> inline cmax(T &a, T b) { a = max(a, b); }
      |                          ^~~~
a.cc: In function 'int cmax(T&, T)':
a.cc:59:59: warning: no return statement in function returning non-void [-Wreturn-type]
   59 | template<class T> inline cmax(T &a, T b) { a = max(a, b); }
      |                                                           ^