Language: C++

#include <algorithm>
#include <iostream>
#include <vector>
#include <map>
using namespace std;

int main() {
    int n, k; cin >> n >> k;
    vector<int> a(n);
    for (auto &ai: a) cin >> ai;
    vector<int> acc(n + 1);
    for (int i = 0; i < n; i++) acc[i + 1] = (acc[i] + a[i]) % k;
    // for (int i = 0; i < n; i++) for (int j = i + 1; j <= n; j++) {
    //     if ((acc[j] - acc[i] + k) % k == j - i) {
    //         cout << i+1 << " " << j << endl;
    //     }
    // }
    vector<int> v(n + 1);
    for (int i = 0; i < n; i++) v[i] = (acc[i] - i % k + k) % k;
    long long ans = 0;
    map<int, int> cnt(k);
    for (int i = 0; i <= n; i++) {
        if (i >= k) cnt[v[i - k]]--;
        ans += cnt[v[i]]++;
    }
    cout << ans << endl;
    return 0;
}

Compiler output:
a.cc: In function 'int main()':
a.cc:21:24: error: no matching function for call to 'std::map<int, int>::map(int&)'
   21 |     map<int, int> cnt(k);
      |                        ^
In file included from /usr/include/c++/14/map:63,
                 from a.cc:4:
/usr/include/c++/14/bits/stl_map.h:302:9: note: candidate: 'template<class _InputIterator> std::map<_Key, _Tp, _Compare, _Alloc>::map(_InputIterator, _InputIterator, const _Compare&, const allocator_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >]'
  302 |         map(_InputIterator __first, _InputIterator __last,
      |         ^~~
/usr/include/c++/14/bits/stl_map.h:302:9: note:   candidate expects 3 arguments, 1 provided
/usr/include/c++/14/bits/stl_map.h:285:9: note: candidate: 'template<class _InputIterator> std::map<_Key, _Tp, _Compare, _Alloc>::map(_InputIterator, _InputIterator) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >]'
  285 |         map(_InputIterator __first, _InputIterator __last)
      |         ^~~
/usr/include/c++/14/bits/stl_map.h:285:9: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_map.h:268:9: note: candidate: 'template<class _InputIterator> std::map<_Key, _Tp, _Compare, _Alloc>::map(_InputIterator, _InputIterator, const allocator_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >]'
  268 |         map(_InputIterator __first, _InputIterator __last,
      |         ^~~
/usr/include/c++/14/bits/stl_map.h:268:9: note:   candidate expects 3 arguments, 1 provided
/usr/include/c++/14/bits/stl_map.h:262:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(std::initializer_list<std::pair<const _Key, _Tp> >, const allocator_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >; allocator_type = std::allocator<std::pair<const int, int> >]'
  262 |       map(initializer_list<value_type> __l, const allocator_type& __a)
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:262:7: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_map.h:256:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(std::map<_Key, _Tp, _Compare, _Alloc>&&, std::__type_identity_t<_Alloc>&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >; std::__type_identity_t<_Alloc> = std::allocator<std::pair<const int, int> >]'
  256 |       map(map&& __m, const __type_identity_t<allocator_type>& __a)
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:256:7: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_map.h:252:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(const std::map<_Key, _Tp, _Compare, _Alloc>&, std::__type_identity_t<_Alloc>&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >; std::__type_identity_t<_Alloc> = std::allocator<std::pair<const int, int> >]'
  252 |       map(const map& __m, const __type_identity_t<allocator_type>& __a)
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:252:7: note:   candidate expects 2 arguments, 1 provided
/usr/include/c++/14/bits/stl_map.h:248:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(const allocator_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >; allocator_type = std::allocator<std::pair<const int, int> >]'
  248 |       map(const allocator_type& __a)
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:248:33: note:   no known conversion for argument 1 from 'int' to 'const std::map<int, int>::allocator_type&' {aka 'const std::allocator<std::pair<const int, int> >&'}
  248 |       map(const allocator_type& __a)
      |           ~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_map.h:240:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(std::initializer_list<std::pair<const _Key, _Tp> >, const _Compare&, const allocator_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >; allocator_type = std::allocator<std::pair<const int, int> >]'
  240 |       map(initializer_list<value_type> __l,
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:240:40: note:   no known conversion for argument 1 from 'int' to 'std::initializer_list<std::pair<const int, int> >'
  240 |       map(initializer_list<value_type> __l,
      |           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~
/usr/include/c++/14/bits/stl_map.h:227:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(std::map<_Key, _Tp, _Compare, _Alloc>&&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >]'
  227 |       map(map&&) = default;
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:227:11: note:   no known conversion for argument 1 from 'int' to 'std::map<int, int>&&'
  227 |       map(map&&) = default;
      |           ^~~~~
/usr/include/c++/14/bits/stl_map.h:219:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(const std::map<_Key, _Tp, _Compare, _Alloc>&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >]'
  219 |       map(const map&) = default;
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:219:11: note:   no known conversion for argument 1 from 'int' to 'const std::map<int, int>&'
  219 |       map(const map&) = default;
      |           ^~~~~~~~~~
/usr/include/c++/14/bits/stl_map.h:206:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map(const _Compare&, const allocator_type&) [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >; allocator_type = std::allocator<std::pair<const int, int> >]'
  206 |       map(const _Compare& __comp,
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:206:27: note:   no known conversion for argument 1 from 'int' to 'const std::less<int>&'
  206 |       map(const _Compare& __comp,
      |           ~~~~~~~~~~~~~~~~^~~~~~
/usr/include/c++/14/bits/stl_map.h:197:7: note: candidate: 'std::map<_Key, _Tp, _Compare, _Alloc>::map() [with _Key = int; _Tp = int; _Compare = std::less<int>; _Alloc = std::allocator<std::pair<const int, int> >]'
  197 |       map() = default;
      |       ^~~
/usr/include/c++/14/bits/stl_map.h:197:7: note:   candidate expects 0 arguments, 1 provided