Submission #172627

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
172627	2020-01-02T08:33:06 Z	dolphingarlic	Land of the Rainbow Gold (APIO17_rainbow)	C++14	Compilation error	0 ms	0 KB

rainbow

/*
APIO 2017 Rainbow
- We can view a rectangle as a planar graph
    - Put temporary rivers on the outside of the rectangle
    - Each river segment is a node and adjacent rivers constitute an edge
- This problem then becomes finding the number of faces of a planar graph
- We can solve this with Euler's formula
- By Euler's formula, we have
    F = E - V + 1 + C
  where F is faces, E is edges, V is vertices, and C is the number of components
- Each corner of a square is a vertex and each side of a square is an edge if it has a river
*/

#include "rainbow.h"
#include <bits/stdc++.h>
#define FOR(i, x, y) for (int i = x; i < y; i++)
using namespace std;

int rnd() { return ((rand() % (1 << 15)) << 16) + (rand() % (1 << 15)); }

struct TreapNode {
    TreapNode *l, *r;
    int pos, key, mn, mx;
    int val, g;
    
    TreapNode(int position, int value) {
        l = r = nullptr;
        mn = mx = pos = position;
        key = rnd();
        val = g = value;
    }

    void update() {
        g = val;
        if (l) g += l->g;
        if (r) g += r->g;
        mn = (l ? l->mn : pos);
        mx = (r ? r->mx : pos);
    }
};

struct Treap {
    TreapNode *root;

    Treap() {
        root = nullptr;
        srand(rnd());
    }

    void split(TreapNode *t, int pos, TreapNode *&l, TreapNode *&r) {
        if (t == nullptr) {
            l = r = nullptr;
            return;
        }
        if (t->pos < pos) {
            split(t->r, pos, l, r);
            t->r = l;
            l = t;
        } else {
            split(t->l, pos, l, r);
            t->l = r;
            r = t;
        }
        t->update();
    }

    TreapNode* merge(TreapNode *l, TreapNode *r) {
        if (!l || !r) return l ? l : r;
        if (l->key < r->key) {
            l->r = merge(l->r, r);
            l->update();
            return l;
        } else {
            r->l = merge(l, r->l);
            r->update();
            return r;
        }
    }

    bool find(int pos) {
        TreapNode *t = root;
        while (t) {
            if (t->pos == pos) return true;
            if (t->pos > pos) t = t->l;
            else t = t->r;
        }
        return false;
    }

    void update(TreapNode *t, int pos, int val) {
        if (t->pos == pos) {
            t->val = val;
            t->update();
            return;
        }
        if (t->pos > pos) update(t->l, pos, val);
        else update(t->r, pos, val);
        t->update();
    }

    void insert(int pos, int val) {
        if (find(pos)) update(root, pos, val);
        else {
            TreapNode *l, *r;
            split(root, pos, l, r);
            root = merge(merge(l, new TreapNode(pos, val)), r);
        }
    }

    int query(TreapNode *t, int st, int en) {
        if (t->mx < st || en < t->mn) return 0;
        if (st <= t->mn && t->mx <= en) return t->g;
        
        int ans = (st <= t->pos && t->pos <= en ? t->val : 0);
        if (t->l) ans += query(t->l, st, en);
        if (t->r) ans += query(t->r, st, en);
        return ans;
    }
    int query(int st, int en) {
        if (!root) return 0;
        return query(root, st, en);
    }
};

struct Segtree {
    Segtree *l, *r;
    Treap treap;
    int lo, hi;

    Segtree() { l = r = nullptr; }
    Segtree(int st, int en) {
        l = r = nullptr;
        lo = st, hi = en;
    }

    void new_left() {
        if (!l) l = new Segtree(lo, (lo + hi) / 2);
    }
    void new_right() {
        if (!r) r = new Segtree((lo + hi) / 2 + 1, hi);
    }
    void fix(int pos) {
        int val = 0;
        if (l) val += l->treap.query(pos, pos);
        if (r) val += r->treap.query(pos, pos);
        treap.insert(pos, val);
    }

    void update(int x, int y, int val) {
        if (hi < x || x < lo) return;
        if (lo == hi) {
            treap.insert(y, val);
            return;
        }

        if (x <= (lo + hi) / 2) {
            new_left();
            l->update(x, y, val);
        } else {
            new_right();
            r->update(x, y, val);
        }
        fix(y);
    }

    int query(int t, int b, int st, int en) {
        if (hi < t || b < lo) return 0;
        if (t <= lo && hi <= b) return treap.query(st, en);

        int ans = 0;
        if (l) ans += l->query(t, b, st, en);
        if (r) ans += r->query(t, b, st, en);
        return ans;
    }
};

Segtree vertices, edges, rivers;
unordered_set<pair<int, int>> v, e, r;
int mx_r, mn_r, mx_c, mn_c;

void add_river(int x, int y) {
    v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
    e.insert({2 * x - 1, 2 * y}); e.insert({2 * x + 1, 2 * y});
    e.insert({2 * x, 2 * y - 1}); e.insert({2 * x, 2 * y + 1});
    r.insert({x, y});
}

void init(int R, int C, int sr, int sc, int M, char *S) {
    srand(12341234);
    vertices = Segtree(1, R + 1);
    edges = Segtree(1, 2 * R + 1);
    rivers = Segtree(1, R);

    add_river(sr, sc);
    mx_r = mn_r = sr;
    mx_c = mn_c = sc;
    FOR(i, 0, M) {
        if (S[i] == 'N') sr--;
        if (S[i] == 'E') sc++;
        if (S[i] == 'S') sr++;
        if (S[i] == 'W') sc--;
        add_river(sr, sc);
        mx_r = max(mx_r, sr);
        mn_r = min(mn_r, sr);
        mx_c = max(mx_c, sc);
        mn_c = min(mn_c, sc);
    }

    for (pair<int, int> i : v) vertices.update(i.first, i.second, 1);
    for (pair<int, int> i : e) edges.update(i.first, i.second, 1);
    for (pair<int, int> i : r) rivers.update(i.first, i.second, 1);
}

int colour(int ar, int ac, int br, int bc) {
    int E = edges.query(2 * ar, 2 * br, 2 * ac, 2 * bc);
    int V = vertices.query(ar + 1, br, ac + 1, bc);
    int R = rivers.query(ar, br, ac, bc);
    int C = (ar >= mn_r || br <= mx_r || ac >= mn_c || bc <= mx_c ? 1 : 2);
    return E - V + C - R;
}

Compilation message

In file included from /usr/include/c++/7/bits/hashtable.h:35:0,
                 from /usr/include/c++/7/unordered_map:47,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:117,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/hashtable_policy.h: In instantiation of 'struct std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > >':
/usr/include/c++/7/type_traits:143:12:   required from 'struct std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > >'
/usr/include/c++/7/type_traits:154:31:   required from 'struct std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
/usr/include/c++/7/bits/unordered_set.h:98:63:   required from 'class std::unordered_set<std::pair<int, int> >'
rainbow.cpp:178:31:   required from here
/usr/include/c++/7/bits/hashtable_policy.h:87:34: error: no match for call to '(const std::hash<std::pair<int, int> >) (const std::pair<int, int>&)'
  noexcept(declval<const _Hash&>()(declval<const _Key&>()))>
           ~~~~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
In file included from /usr/include/c++/7/bits/move.h:54:0,
                 from /usr/include/c++/7/bits/nested_exception.h:40,
                 from /usr/include/c++/7/exception:143,
                 from /usr/include/c++/7/ios:39,
                 from /usr/include/c++/7/istream:38,
                 from /usr/include/c++/7/sstream:38,
                 from /usr/include/c++/7/complex:45,
                 from /usr/include/c++/7/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:52,
                 from rainbow.cpp:15:
/usr/include/c++/7/type_traits: In instantiation of 'struct std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >':
/usr/include/c++/7/bits/unordered_set.h:98:63:   required from 'class std::unordered_set<std::pair<int, int> >'
rainbow.cpp:178:31:   required from here
/usr/include/c++/7/type_traits:154:31: error: 'value' is not a member of 'std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > >'
     : public __bool_constant<!bool(_Pp::value)>
                               ^~~~~~~~~~~~~~~~
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h: In instantiation of 'class std::unordered_set<std::pair<int, int> >':
rainbow.cpp:178:31:   required from here
/usr/include/c++/7/bits/unordered_set.h:98:63: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef __uset_hashtable<_Value, _Hash, _Pred, _Alloc>  _Hashtable;
                                                               ^~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:105:45: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::key_type key_type;
                                             ^~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:106:47: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::value_type value_type;
                                               ^~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:107:43: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::hasher hasher;
                                           ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:108:46: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::key_equal key_equal;
                                              ^~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:109:51: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::allocator_type allocator_type;
                                                   ^~~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:114:45: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::pointer  pointer;
                                             ^~~~~~~
/usr/include/c++/7/bits/unordered_set.h:115:50: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::const_pointer const_pointer;
                                                  ^~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:116:47: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::reference  reference;
                                               ^~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:117:52: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::const_reference const_reference;
                                                    ^~~~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:118:46: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::iterator  iterator;
                                              ^~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:119:51: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::const_iterator const_iterator;
                                                   ^~~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:120:51: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::local_iterator local_iterator;
                                                   ^~~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:121:57: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::const_local_iterator const_local_iterator;
                                                         ^~~~~~~~~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:122:47: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::size_type  size_type;
                                               ^~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:123:52: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       typedef typename _Hashtable::difference_type difference_type;
                                                    ^~~~~~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:282:7: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       operator=(initializer_list<value_type> __l)
       ^~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:375:2: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
  emplace(_Args&&... __args)
  ^~~~~~~
/usr/include/c++/7/bits/unordered_set.h:419:7: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       insert(const value_type& __x)
       ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:423:7: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       insert(value_type&& __x)
       ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:478:7: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       insert(initializer_list<value_type> __l)
       ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:679:7: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       equal_range(const key_type& __x)
       ^~~~~~~~~~~
/usr/include/c++/7/bits/unordered_set.h:683:7: error: 'value' is not a member of 'std::__not_<std::__and_<std::__is_fast_hash<std::hash<std::pair<int, int> > >, std::__detail::__is_noexcept_hash<std::pair<int, int>, std::hash<std::pair<int, int> > > > >'
       equal_range(const key_type& __x) const
       ^~~~~~~~~~~
rainbow.cpp: In function 'void add_river(int, int)':
rainbow.cpp:182:20: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                    ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::hash<std::pair<int, int> >; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >]
  insert(_InputIterator __first, _InputIterator __last)
  ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:467:2: note:   template argument deduction/substitution failed:
rainbow.cpp:182:20: note:   candidate expects 2 arguments, 1 provided
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                    ^
rainbow.cpp:182:42: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                                          ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::hash<std::pair<int, int> >; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >]
  insert(_InputIterator __first, _InputIterator __last)
  ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:467:2: note:   template argument deduction/substitution failed:
rainbow.cpp:182:42: note:   candidate expects 2 arguments, 1 provided
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                                          ^
rainbow.cpp:182:64: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                                                                ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::hash<std::pair<int, int> >; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >]
  insert(_InputIterator __first, _InputIterator __last)
  ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:467:2: note:   template argument deduction/substitution failed:
rainbow.cpp:182:64: note:   candidate expects 2 arguments, 1 provided
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                                                                ^
rainbow.cpp:182:90: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                                                                                          ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::hash<std::pair<int, int> >; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >]
  insert(_InputIterator __first, _InputIterator __last)
  ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:467:2: note:   template argument deduction/substitution failed:
rainbow.cpp:182:90: note:   candidate expects 2 arguments, 1 provided
     v.insert({x, y}); v.insert({x + 1, y}); v.insert({x, y + 1}); v.insert({x + 1, y + 1});
                                                                                          ^
rainbow.cpp:183:32: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     e.insert({2 * x - 1, 2 * y}); e.insert({2 * x + 1, 2 * y});
                                ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::hash<std::pair<int, int> >; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >]
  insert(_InputIterator __first, _InputIterator __last)
  ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:467:2: note:   template argument deduction/substitution failed:
rainbow.cpp:183:32: note:   candidate expects 2 arguments, 1 provided
     e.insert({2 * x - 1, 2 * y}); e.insert({2 * x + 1, 2 * y});
                                ^
rainbow.cpp:183:62: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     e.insert({2 * x - 1, 2 * y}); e.insert({2 * x + 1, 2 * y});
                                                              ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::hash<std::pair<int, int> >; _Pred = std::equal_to<std::pair<int, int> >; _Alloc = std::allocator<std::pair<int, int> >]
  insert(_InputIterator __first, _InputIterator __last)
  ^~~~~~
/usr/include/c++/7/bits/unordered_set.h:467:2: note:   template argument deduction/substitution failed:
rainbow.cpp:183:62: note:   candidate expects 2 arguments, 1 provided
     e.insert({2 * x - 1, 2 * y}); e.insert({2 * x + 1, 2 * y});
                                                              ^
rainbow.cpp:184:32: error: no matching function for call to 'std::unordered_set<std::pair<int, int> >::insert(<brace-enclosed initializer list>)'
     e.insert({2 * x, 2 * y - 1}); e.insert({2 * x, 2 * y + 1});
                                ^
In file included from /usr/include/c++/7/unordered_set:48:0,
                 from /usr/include/x86_64-linux-gnu/c++/7/bits/stdc++.h:118,
                 from rainbow.cpp:15:
/usr/include/c++/7/bits/unordered_set.h:467:2: note: candidate: template<class _InputIterator> void std::unordered_set<_Value, _Hash, _Pred, _Alloc>::insert(_InputIterator, _InputIterator) [with _InputIterator = _InputIterator; _Value = std::pair<int, int>; _Hash = std::ha