Language: C++

// >>> TEMPLATES
#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
#define int ll
#define double ld
#define rep(i,n) for (int i = 0; i < (int)(n); i++)
#define rep1(i,n) for (int i = 1; i <= (int)(n); i++)
#define repR(i,n) for (int i = (int)(n)-1; i >= 0; i--)
#define rep1R(i,n) for (int i = (int)(n); i >= 1; i--)
#define loop(i,a,B) for (int i = a; i B; i++)
#define loopR(i,a,B) for (int i = a; i B; i--)
#define all(x) (x).begin(), (x).end()
#define allR(x) (x).rbegin(), (x).rend()
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fst first
#define snd second
#define INF (numeric_limits<int>::max()/2-1)
#ifdef LOCAL
#define dump(...) cerr << "[" << __LINE__ << ":" << __FUNCTION__ << "] ", dump_impl(#__VA_ARGS__, __VA_ARGS__)
#define say(x) cerr << "[" << __LINE__ << ":" << __FUNCTION__ << "] " << x << endl
#define debug if (1)
void dump_impl(const char*) { cerr << endl; }
template <class T, class... U> void dump_impl(const char *s, T const& x, U const& ...y) { const char *o = "({[", *e = "]})"; for (int i = 0; *s != '\0'; cerr << *s++) { if (count(o,o+3,*s)) i++; if (count(e,e+3,*s)) i--; if (!i && *s == ',') break; } cerr << " = " << x; if (*s == ',') cerr << ", ", s++; dump_impl(s, y...); }
#else
#define dump(...) (void)(0)
#define say(x) (void)(0)
#define debug if (0)
#endif
template <class T> using pque_max = priority_queue<T>;
template <class T> using pque_min = priority_queue<T, vector<T>, greater<T> >;
template <class T, class = typename T::iterator, class = typename enable_if<!is_same<T, string>::value>::type>
ostream& operator<<(ostream& os, T const& v) { os << "{"; for (auto const& x : v) os << " " << x; return os << " }"; }
template <class T, class = typename T::iterator, class = typename enable_if<!is_same<T, string>::value>::type>
istream& operator>>(istream& is, T &v) { for (auto& x : v) is >> x; return is; }
template <class T, class S> ostream& operator<<(ostream& os, pair<T,S> const& p) { return os << "(" << p.first << ", " << p.second << ")"; }
template <class T, class S> istream& operator>>(istream& is, pair<T,S>& p) { return is >> p.first >> p.second; }
template <size_t i, class T> typename enable_if<i >= tuple_size<T>::value>::type output_tuple(ostream&, T const&) { }
template <size_t i = 0, class T> typename enable_if<i < tuple_size<T>::value>::type
output_tuple(ostream& os, T const& t) { os << (i ? " " : "") << get<i>(t); output_tuple<i+1,T>(os,t); }
template <class... T> ostream& operator<<(ostream& os, tuple<T...> const& t) { return output_tuple(os,t), os; }
struct IOSetup { IOSetup() { cin.tie(nullptr); ios::sync_with_stdio(false); cout << fixed << setprecision(15); } } iosetup;
template <class F> struct FixPoint : private F {
    constexpr FixPoint(F&& f) : F(forward<F>(f)) {}
    template <class... T> constexpr auto operator()(T&&... x) const { return F::operator()(*this, forward<T>(x)...); }
};
struct MakeFixPoint {
    template <class F> constexpr auto operator|(F&& f) const { return FixPoint<F>(forward<F>(f)); }
};
#define MFP MakeFixPoint()|
#define def(name, ...) auto name = MFP [&](auto &&name, __VA_ARGS__)
template <class T, size_t d> struct vec_impl {
    using type = vector<typename vec_impl<T,d-1>::type>;
    template <class... U> static type make_v(size_t n, U&&... x) { return type(n, vec_impl<T,d-1>::make_v(forward<U>(x)...)); }
};
template <class T> struct vec_impl<T,0> { using type = T; static type make_v(T const& x = {}) { return x; } };
template <class T, size_t d = 1> using vec = typename vec_impl<T,d>::type;
template <class T, size_t d = 1, class... Args> auto make_v(Args&&... args) { return vec_impl<T,d>::make_v(forward<Args>(args)...); }
template <class T> void quit(T const& x) { cout << x << endl; exit(0); }
template <class T> constexpr bool chmin(T& x, T const& y) { if (x > y) { x = y; return true; } return false; }
template <class T> constexpr bool chmax(T& x, T const& y) { if (x < y) { x = y; return true; } return false; }
template <class It> constexpr auto sumof(It b, It e) { return accumulate(b,e,typename iterator_traits<It>::value_type{}); }
template <class T> int sz(T const& x) { return x.size(); }
// <<<
// >>> NTT
template <class ModInt, int64_t p, int64_t g>
struct NTT {
    static const int64_t mod = p, gen = g, max_lg = __builtin_ctzll(p-1);
    // p:prime, g:primitive root of p
    static_assert(p > 0 && g > 0 && max_lg > 0, "");

    static array<ModInt,max_lg+1> ws,iws;
    static void init() {
        for (int i = 0; i <= max_lg; i++) {
            ws[i] = ModInt(g).pow((p-1)>>i);
            iws[i] = ModInt(1)/ws[i];
        }
    }
    static void ntt(ModInt a[], int lg) {
        for (int b = lg-1; b >= 0; b--) {
            for (int i = 0; i < (1<<lg); i += 1<<(b+1)) {
                ModInt w = 1, r = ws[b+1];
                for (int j = i; j < (i|(1<<b)); j++, w *= r) {
                    const int k = j|(1<<b);
                    const auto x = a[j], y = a[k];
                    a[j] = x + y;
                    a[k] = w*(x - y);
                }
            }
        }
//        bit_reverse(a,1<<lg);
    }
    static void intt(ModInt a[], int lg) {
//        bit_reverse(a,1<<lg);
        for (int b = 0; b < lg; b++) {
            for (int i = 0; i < (1<<lg); i += 1<<(b+1)) {
                ModInt w = 1, r = iws[b+1];
                for (int j = i; j < (i|(1<<b)); j++, w *= r) {
                    const int k = j|(1<<b);
                    const auto x = a[j], y = a[k];
                    a[j] = x + y*w;
                    a[k] = x - y*w;
                }
            }
        }
    }
    static vector<ModInt> conv(vector<ModInt> a, vector<ModInt> b) {
        if (a.empty() || b.empty()) return {};
        init();
        const int s = a.size() + b.size() - 1, lg = __lg(2*s-1);
        assert(lg <= max_lg);
        a.resize(1<<lg); ntt(a.data(), lg);
        b.resize(1<<lg); ntt(b.data(), lg);
        const auto x = ModInt(1)/ModInt(1<<lg);
        rep (i,1<<lg) a[i] *= b[i]*x;
        intt(a.data(), lg); a.resize(s);
        return a;
    }
};
template <class ModInt, int64_t p, int64_t g>
array<ModInt,NTT<ModInt,p,g>::max_lg+1> NTT<ModInt,p,g>::ws;
template <class ModInt, int64_t p, int64_t g>
array<ModInt,NTT<ModInt,p,g>::max_lg+1> NTT<ModInt,p,g>::iws;
// <<<

// >>> modint
template <int32_t mod>
class modint {
    static_assert(mod > 0, "");
    using M = modint;
    using ll = int64_t;
    int32_t x;
public:
    constexpr modint(ll x = 0) : x((x%=mod) < 0 ? x+mod : x) { }
    constexpr M take_mod() const { return x; }
    constexpr ll val() const { return x; }
    constexpr bool operator==(M const& r) const { return x == r.x; }
    constexpr bool operator!=(M const& r) const { return x != r.x; }
    constexpr M operator+() const { return *this; }
    constexpr M operator-() const { return M()-*this; }
    constexpr M& operator+=(M const& r) { if ((x += r.x) >= mod) x -= mod; return *this; }
    constexpr M& operator-=(M const& r) { if ((x += mod-r.x) >= mod) x -= mod; return *this; }
    constexpr M& operator*=(M const& r) { return *this = *this * r; }
    constexpr M operator*(M const& r) const { M t; t.x = (ll(x)*r.x) % mod; return t; }
    constexpr M& operator/=(M const& r) { return *this *= r.inv(); }
    constexpr M operator+(M const& r) const { return M(*this) += r; }
    constexpr M operator-(M const& r) const { return M(*this) -= r; }
    constexpr M operator/(M const& r) const { return M(*this) /= r; }
    friend constexpr M operator+(ll x, M const& y) { return M(x)+y; }
    friend constexpr M operator-(ll x, M const& y) { return M(x)-y; }
    friend constexpr M operator*(ll x, M const& y) { return M(x)*y; }
    friend constexpr M operator/(ll x, M const& y) { return M(x)/y; }
    constexpr M pow(ll n) const {
        if (n < 0) return inv().pow(-n);
        M v = *this, r = 1;
        for (; n > 0; n >>= 1, v *= v) if (n&1) r *= v;
        return r;
    }
    constexpr M inv() const {
        assert(x > 0);
        ll t = 1, v = x, q = 0, r = 0;
        while (v != 1) {
            q = mod / v; r = mod % v;
            if (r * 2 < v) {
                t *= -q; t %= mod; v = r;
            } else {
                t *= q + 1; t %= mod; v -= r;
            }
        }
        if (t < 0) t += mod;
        M y; y.x = t; return y;
    }
};
template <int32_t MOD> ostream& operator<<(ostream& os, modint<MOD> const& r) { return os << r.val(); }
template <int32_t MOD> istream& operator>>(istream& is, modint<MOD> &r) { int64_t x; is >> x; r = x; return is; }
// <<<
constexpr int64_t MOD = 167772161; // 2^25 * 5 + 1
using mint = modint<(int32_t)MOD>;
using ntt = NTT<mint,MOD,3>;

int32_t main() {
    int n,m; cin >> n >> m;
    vector<int> a(n); cin >> a;

    const int NN = 1e5 + 10;
    vector<mint> v(NN);
    rep (i,n) v[a[i]] += 1;
    auto res = ntt::conv(v,v);

    int ans = 0, sum = 0;
    loopR (x,2*NN-2,>=0) {
        int val = min(res[x].val(),m-sum);
        sum += val;
        ans += val*x;
        if (sum >= m) break;
    }
    cout << ans << endl;
}


Compiler output:
a.cc: In function 'int32_t main()':
a.cc:195:22: error: no matching function for call to 'min(modint<167772161>::ll, ll)'
  195 |         int val = min(res[x].val(),m-sum);
      |                   ~~~^~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/14/algorithm:60,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:51,
                 from a.cc:2:
/usr/include/c++/14/bits/stl_algobase.h:233:5: note: candidate: 'template<class _Tp> constexpr const _Tp& std::min(const _Tp&, const _Tp&)'
  233 |     min(const _Tp& __a, const _Tp& __b)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:233:5: note:   template argument deduction/substitution failed:
a.cc:195:22: note:   deduced conflicting types for parameter 'const _Tp' ('long int' and 'll' {aka 'long long int'})
  195 |         int val = min(res[x].val(),m-sum);
      |                   ~~~^~~~~~~~~~~~~~~~~~~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: note: candidate: 'template<class _Tp, class _Compare> constexpr const _Tp& std::min(const _Tp&, const _Tp&, _Compare)'
  281 |     min(const _Tp& __a, const _Tp& __b, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algobase.h:281:5: note:   candidate expects 3 arguments, 2 provided
In file included from /usr/include/c++/14/algorithm:61:
/usr/include/c++/14/bits/stl_algo.h:5686:5: note: candidate: 'template<class _Tp> constexpr _Tp std::min(initializer_list<_Tp>)'
 5686 |     min(initializer_list<_Tp> __l)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5686:5: note:   candidate expects 1 argument, 2 provided
/usr/include/c++/14/bits/stl_algo.h:5696:5: note: candidate: 'template<class _Tp, class _Compare> constexpr _Tp std::min(initializer_list<_Tp>, _Compare)'
 5696 |     min(initializer_list<_Tp> __l, _Compare __comp)
      |     ^~~
/usr/include/c++/14/bits/stl_algo.h:5696:5: note:   template argument deduction/substitution failed:
a.cc:195:22: note:   mismatched types 'std::initializer_list<_Tp>' and 'long int'
  195 |         int val = min(res[x].val(),m-sum);
      |                   ~~~^~~~~~~~~~~~~~~~~~~~