Submission #637906

#	Time	Username	Problem	Language	Result	Execution time	Memory
637906		ionan6ix	Aliens (IOI16_aliens)	C++17	Compilation error	0 ms	0 KiB

aliens

#include "aliens.h"
#include<bits/stdc++.h>

using namespace std;

#pragma once
#define rep(i, a, b) for(int i = a; i < (b); ++i)
#define all(x) begin(x), end(x)
#define sz(x) (int)(x).size()
typedef long long ll;
typedef pair<int, int> pii;
typedef vector<int> vi;
struct Line {
    mutable ll k, m, p;
    bool operator<(const Line& o) const { return k < o.k; }
    bool operator<(ll x) const { return p < x; }
};

map<pair<ll,ll>,int > M;

struct LineContainer : multiset<Line, greater<>> {
    // (for doubles, use inf = 1/.0, div(a,b) = a/b)
    static const ll inf = LLONG_MAX;
    ll div(ll a, ll b) { // floored division
        return a / b - ((a ^ b) < 0 && a % b); }
    bool isect(iterator x, iterator y) {
        if (y == end()) return x->p = inf, 0;
        if (x->k == y->k) x->p = x->m > y->m ? inf : -inf;
        else x->p = div(y->m - x->m, x->k - y->k);
        return x->p >= y->p;
    }
    void add(ll k, ll m) {
        auto z = insert({k, m, 0}), y = z++, x = y;
        while (isect(y, z)) z = erase(z);
        if (x != begin() && isect(--x, y)) isect(x, y = erase(y));
        while ((y = x) != begin() && (--x)->p >= y->p)
            isect(x, erase(y));
    }
    ll query(ll x) {
        assert(!empty());
        auto l = *lower_bound(x);
        return l.k * x + l.m;
    }

    Line getLine(ll x)
    {
        assert(!empty());
        auto l = *lower_bound(x);
        return l;
    }
};

bool cmp(pair<long long,long long> a,pair<long long,long long> b)
{
    if(a.first==b.first)
        return a.second>b.second;

    return a.first<b.first;
}

bool inters(pair<int,int> a,pair<int,int> b)
{
    if(a.first<=b.first && a.second>=b.second)
        return true;
    return false;
}

pair<ll,ll> pics(long long penalty,int n,int m,vector<int>& r,vector<int>& c)
{
    vector<pair<long long,long long> > obj;
    vector<pair<long long,long long> > aux;
    for(int i = 0;i<n;i++)
        aux.emplace_back(1LL*min(r[i],c[i]),1LL*max(r[i],c[i]));

    sort(aux.begin(),aux.end(),cmp);

    obj.emplace_back(-1,-1);

    for(auto it:aux)
    {
        if(!inters(obj.back(),it))
            obj.push_back(it);
    }

    M.clear();
    n = obj.size();
    vector<long long> dp;
    vector<int> pics;
    dp.resize(n+1);
    pics.resize(n+1);

    LineContainer lc;
    lc.clear();

    lc.add(-2*obj[1].first,dp[0]+obj[1].first*obj[1].first);
    M[make_pair(-2*obj[1].first,dp[0]+obj[1].first*obj[1].first)] = 0;

    for(int i=1;i<n;i++)
    {
        long long zi = obj[i].second+1;

        Line best = lc.getLine(zi);
        long long res = lc.query(zi);

        dp[i] = res + zi * zi + penalty;

        pics[i] = 1 + M[make_pair(best.k,best.m)];

        if(i==(n-1)) continue;

        long long intersection = max(0LL,obj[i].second-obj[i+1].first+1LL)*max(0LL,obj[i].second-obj[i+1].first+1LL);
        long long a = -2 * obj[i + 1].first;
        long long b = dp[i] + obj[i + 1].first * obj[i + 1].first - intersection;

        lc.add(a,b);

        M[make_pair(a,b)] = pics[i];
    }

    return make_pair(dp[n-1],pics[n-1]);

}
long long take_photos(int n, int m, int k, std::vector<int> r, std::vector<int> c) {

    long long st = 0;
    long long dr = 1LL*m*m;
    long long sol;
    pair<ll,ll> best;

    while(st<=dr)
    {
        long long mid = (st+dr)>>1;

        if(pics(mid,n,m,r,c).second<=k)
        {
            sol=mid;
            best = pics(mid,n,m,r,c);
            dr = mid-1;
        }
        else st = mid+1;

    }

    return best.first - sol * best.second;
}

Compilation message (stderr)

aliens.cpp:6:9: warning: #pragma once in main file
    6 | #pragma once
      |         ^~~~
In file included from /usr/include/c++/10/map:60,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:81,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_tree.h: In instantiation of 'std::pair<std::_Rb_tree_node_base*, std::_Rb_tree_node_base*> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_get_insert_equal_pos(const key_type&) [with _Key = Line; _Val = Line; _KeyOfValue = std::_Identity<Line>; _Compare = std::greater<void>; _Alloc = std::allocator<Line>; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::key_type = Line]':
/usr/include/c++/10/bits/stl_tree.h:2181:4:   required from 'std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_equal(_Arg&&) [with _Arg = Line; _Key = Line; _Val = Line; _KeyOfValue = std::_Identity<Line>; _Compare = std::greater<void>; _Alloc = std::allocator<Line>; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator = std::_Rb_tree<Line, Line, std::_Identity<Line>, std::greater<void>, std::allocator<Line> >::iterator]'
/usr/include/c++/10/bits/stl_multiset.h:508:36:   required from 'std::multiset<_Key, _Compare, _Alloc>::iterator std::multiset<_Key, _Compare, _Alloc>::insert(std::multiset<_Key, _Compare, _Alloc>::value_type&&) [with _Key = Line; _Compare = std::greater<void>; _Alloc = std::allocator<Line>; std::multiset<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<Line, Line, std::_Identity<Line>, std::greater<void>, std::allocator<Line> >::const_iterator; std::multiset<_Key, _Compare, _Alloc>::value_type = Line]'
aliens.cpp:33:34:   required from here
/usr/include/c++/10/bits/stl_tree.h:2132:32: error: no match for call to '(std::greater<void>) (const key_type&, const Line&)'
 2132 |    __x = _M_impl._M_key_compare(__k, _S_key(__x)) ?
      |          ~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:520:2: note: candidate: 'template<class _Tp, class _Up> constexpr decltype ((forward<_Tp>(__t) > forward<_Up>(__u))) std::greater<void>::operator()(_Tp&&, _Up&&) const'
  520 |  operator()(_Tp&& __t, _Up&& __u) const
      |  ^~~~~~~~
/usr/include/c++/10/bits/stl_function.h:520:2: note:   template argument deduction/substitution failed:
/usr/include/c++/10/bits/stl_function.h: In substitution of 'template<class _Tp, class _Up> constexpr decltype ((forward<_Tp>(__t) > forward<_Up>(__u))) std::greater<void>::operator()(_Tp&&, _Up&&) const [with _Tp = const Line&; _Up = const Line&]':
/usr/include/c++/10/bits/stl_tree.h:2132:32:   required from 'std::pair<std::_Rb_tree_node_base*, std::_Rb_tree_node_base*> std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_get_insert_equal_pos(const key_type&) [with _Key = Line; _Val = Line; _KeyOfValue = std::_Identity<Line>; _Compare = std::greater<void>; _Alloc = std::allocator<Line>; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::key_type = Line]'
/usr/include/c++/10/bits/stl_tree.h:2181:4:   required from 'std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::_M_insert_equal(_Arg&&) [with _Arg = Line; _Key = Line; _Val = Line; _KeyOfValue = std::_Identity<Line>; _Compare = std::greater<void>; _Alloc = std::allocator<Line>; std::_Rb_tree<_Key, _Val, _KeyOfValue, _Compare, _Alloc>::iterator = std::_Rb_tree<Line, Line, std::_Identity<Line>, std::greater<void>, std::allocator<Line> >::iterator]'
/usr/include/c++/10/bits/stl_multiset.h:508:36:   required from 'std::multiset<_Key, _Compare, _Alloc>::iterator std::multiset<_Key, _Compare, _Alloc>::insert(std::multiset<_Key, _Compare, _Alloc>::value_type&&) [with _Key = Line; _Compare = std::greater<void>; _Alloc = std::allocator<Line>; std::multiset<_Key, _Compare, _Alloc>::iterator = std::_Rb_tree<Line, Line, std::_Identity<Line>, std::greater<void>, std::allocator<Line> >::const_iterator; std::multiset<_Key, _Compare, _Alloc>::value_type = Line]'
aliens.cpp:33:34:   required from here
/usr/include/c++/10/bits/stl_function.h:522:37: error: no match for 'operator>' (operand types are 'const Line' and 'const Line')
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/stl_algobase.h:64,
                 from /usr/include/c++/10/vector:60,
                 from aliens.h:3,
                 from aliens.cpp:1:
/usr/include/c++/10/bits/stl_pair.h:502:5: note: candidate: 'template<class _T1, class _T2> constexpr bool std::operator>(const std::pair<_T1, _T2>&, const std::pair<_T1, _T2>&)'
  502 |     operator>(const pair<_T1, _T2>& __x, const pair<_T1, _T2>& __y)
      |     ^~~~~~~~
/usr/include/c++/10/bits/stl_pair.h:502:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'const Line' is not derived from 'const std::pair<_T1, _T2>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/stl_algobase.h:67,
                 from /usr/include/c++/10/vector:60,
                 from aliens.h:3,
                 from aliens.cpp:1:
/usr/include/c++/10/bits/stl_iterator.h:378:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_Iterator>&)'
  378 |     operator>(const reverse_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/10/bits/stl_iterator.h:378:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'const Line' is not derived from 'const std::reverse_iterator<_Iterator>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/stl_algobase.h:67,
                 from /usr/include/c++/10/vector:60,
                 from aliens.h:3,
                 from aliens.cpp:1:
/usr/include/c++/10/bits/stl_iterator.h:416:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>(const std::reverse_iterator<_Iterator>&, const std::reverse_iterator<_IteratorR>&)'
  416 |     operator>(const reverse_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/10/bits/stl_iterator.h:416:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'const Line' is not derived from 'const std::reverse_iterator<_Iterator>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/stl_algobase.h:67,
                 from /usr/include/c++/10/vector:60,
                 from aliens.h:3,
                 from aliens.cpp:1:
/usr/include/c++/10/bits/stl_iterator.h:1469:5: note: candidate: 'template<class _IteratorL, class _IteratorR> constexpr bool std::operator>(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorR>&)'
 1469 |     operator>(const move_iterator<_IteratorL>& __x,
      |     ^~~~~~~~
/usr/include/c++/10/bits/stl_iterator.h:1469:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'const Line' is not derived from 'const std::move_iterator<_IteratorL>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/stl_algobase.h:67,
                 from /usr/include/c++/10/vector:60,
                 from aliens.h:3,
                 from aliens.cpp:1:
/usr/include/c++/10/bits/stl_iterator.h:1519:5: note: candidate: 'template<class _Iterator> constexpr bool std::operator>(const std::move_iterator<_IteratorL>&, const std::move_iterator<_IteratorL>&)'
 1519 |     operator>(const move_iterator<_Iterator>& __x,
      |     ^~~~~~~~
/usr/include/c++/10/bits/stl_iterator.h:1519:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'const Line' is not derived from 'const std::move_iterator<_IteratorL>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/vector:67,
                 from aliens.h:3,
                 from aliens.cpp:1:
/usr/include/c++/10/bits/stl_vector.h:1943:5: note: candidate: 'template<class _Tp, class _Alloc> bool std::operator>(const std::vector<_Tp, _Alloc>&, const std::vector<_Tp, _Alloc>&)'
 1943 |     operator>(const vector<_Tp, _Alloc>& __x, const vector<_Tp, _Alloc>& __y)
      |     ^~~~~~~~
/usr/include/c++/10/bits/stl_vector.h:1943:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'const Line' is not derived from 'const std::vector<_Tp, _Alloc>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/basic_string.h:48,
                 from /usr/include/c++/10/string:55,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/string_view:563:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>(std::basic_string_view<_CharT, _Traits>, std::basic_string_view<_CharT, _Traits>)'
  563 |     operator> (basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/10/string_view:563:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'Line' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/basic_string.h:48,
                 from /usr/include/c++/10/string:55,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/string_view:569:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>(std::basic_string_view<_CharT, _Traits>, std::__type_identity_t<std::basic_string_view<_CharT, _Traits> >)'
  569 |     operator> (basic_string_view<_CharT, _Traits> __x,
      |     ^~~~~~~~
/usr/include/c++/10/string_view:569:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'Line' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/bits/basic_string.h:48,
                 from /usr/include/c++/10/string:55,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/string_view:576:5: note: candidate: 'template<class _CharT, class _Traits> constexpr bool std::operator>(std::__type_identity_t<std::basic_string_view<_CharT, _Traits> >, std::basic_string_view<_CharT, _Traits>)'
  576 |     operator> (__type_identity_t<basic_string_view<_CharT, _Traits>> __x,
      |     ^~~~~~~~
/usr/include/c++/10/string_view:576:5: note:   template argument deduction/substitution failed:
In file included from /usr/include/c++/10/string:48,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c++/10/bits/ios_base.h:41,
                 from /usr/include/c++/10/ios:42,
                 from /usr/include/c++/10/istream:38,
                 from /usr/include/c++/10/sstream:38,
                 from /usr/include/c++/10/complex:45,
                 from /usr/include/c++/10/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/10/bits/stdc++.h:54,
                 from aliens.cpp:2:
/usr/include/c++/10/bits/stl_function.h:522:37: note:   'Line' is not derived from 'std::basic_string_view<_CharT, _Traits>'
  522 |  -> decltype(std::forward<_Tp>(__t) > std::forward<_Up>(__u))
      |              ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/10/string:55,
                 from /usr/include/c++/10/bits/locale_classes.h:40,
                 from /usr/include/c