Language: C++

#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>

#define F first
#define S second
#define int long long
#define ll long long
//#define int  unsigned long long
#define pb push_back
//#define double long double

using namespace std;
using namespace __gnu_pbds;
typedef  tree< int , null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> ordered_set;
const int mod = 1e9 + 7;
const int N = 200005;
const int K = 50;
set < int > g1[N], g2[N];
int s1[N], s2[N], a[N], b[N], x[N];
main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    //freopen("input.txt", "r", stdin);
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++){
        cin >> a[i]--;
    }
    x[1] = a[1];
    for (int i = 2; i <= n; i++){
        int y;
        if (a[i] > a[i - 1]) y = a[i] - a[i - 1]; else
        y = m - (a[i - 1] - a[i]);
        x[i] = x[i - 1] + y;
    }
    for (int i = 2; i <= n; i++){
        if (x[i - 1] - x[i] == 1) continue;
        int l, r;
        if (x[i] % m > x[i - 1] % m){
            l = x[i - 1] % m + 2;
            r = x[i] % m;
        } else{
            l = x[i - 1] % m + 2;
            r = x[i] % m + m;
        }
        s1[l]++;
        s1[r + 1]--;
        int d = r - l + 1;
        s1[r + 1] += (-d);
        s1[r + 2] += d;
    }
    int xx = 0;
    for (int i = 0; i <= m + m + m; i++){
        xx += s1[i];
        s2[i] = xx;
    }
    xx = 0;
    int ans = 0;
    for (int i = 0; i <= m + m + m; i++){
        xx += s2[i];
        b[i] = xx;
    }
    for (int i = 0; i < m; i++){
        ans = max(ans, b[i] + b[i + m] + b[i + m + m]);
    }
   // cout << ans << endl;
    cout << x[n] - x[1] - ans;
}


Compiler output:
a.cc:21:1: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
   21 | main(){
      | ^~~~
a.cc: In function 'int main()':
a.cc:28:13: error: no match for 'operator>>' (operand types are 'std::istream' {aka 'std::basic_istream<char>'} and 'long long int')
   28 |         cin >> a[i]--;
      |         ~~~ ^~ ~~~~~~
      |         |          |
      |         |          long long int
      |         std::istream {aka std::basic_istream<char>}
In file included from /usr/include/c++/14/sstream:40,
                 from /usr/include/c++/14/complex:45,
                 from /usr/include/c++/14/ccomplex:39,
                 from /usr/include/x86_64-linux-gnu/c++/14/bits/stdc++.h:127,
                 from a.cc:2:
/usr/include/c++/14/istream:170:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(bool&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  170 |       operator>>(bool& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:170:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'bool&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:174:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(short int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  174 |       operator>>(short& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:174:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'short int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:177:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(short unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  177 |       operator>>(unsigned short& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:177:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'short unsigned int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:181:7: note: candidate: 'std::basic_istream<_CharT, _Traits>& std::basic_istream<_CharT, _Traits>::operator>>(int&) [with _CharT = char; _Traits = std::char_traits<char>]' (near match)
  181 |       operator>>(int& __n);
      |       ^~~~~~~~
/usr/include/c++/14/istream:181:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:184:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  184 |       operator>>(unsigned int& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:184:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'unsigned int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:188:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  188 |       operator>>(long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:188:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'long int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:192:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  192 |       operator>>(unsigned long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:192:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'long unsigned int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:199:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  199 |       operator>>(long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:199:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'long long int&' to an rvalue of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:203:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long long unsigned int&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  203 |       operator>>(unsigned long long& __n)
      |       ^~~~~~~~
/usr/include/c++/14/istream:203:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'long long unsigned int&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:219:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(float&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  219 |       operator>>(float& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:219:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'float&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:223:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  223 |       operator>>(double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:223:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'double&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:227:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(long double&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  227 |       operator>>(long double& __f)
      |       ^~~~~~~~
/usr/include/c++/14/istream:227:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: cannot bind non-const lvalue reference of type 'long double&' to a value of type 'long long int'
   28 |         cin >> a[i]--;
      |                ~~~~^~
/usr/include/c++/14/istream:328:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(void*&) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  328 |       operator>>(void*& __p)
      |       ^~~~~~~~
/usr/include/c++/14/istream:328:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: invalid conversion from 'long long int' to 'void*' [-fpermissive]
   28 |         cin >> a[i]--;
      |                ~~~~^~
      |                    |
      |                    long long int
a.cc:28:20: error: cannot bind rvalue '(void*)(a[i]--)' to 'void*&'
/usr/include/c++/14/istream:122:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__istream_type& (*)(__istream_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>]' (near match)
  122 |       operator>>(__istream_type& (*__pf)(__istream_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:122:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: invalid conversion from 'long long int' to 'std::basic_istream<char>::__istream_type& (*)(std::basic_istream<char>::__istream_type&)' {aka 'std::basic_istream<char>& (*)(std::basic_istream<char>&)'} [-fpermissive]
   28 |         cin >> a[i]--;
      |                ~~~~^~
      |                    |
      |                    long long int
/usr/include/c++/14/istream:126:7: note: candidate: 'std::basic_istream<_CharT, _Traits>::__istream_type& std::basic_istream<_CharT, _Traits>::operator>>(__ios_type& (*)(__ios_type&)) [with _CharT = char; _Traits = std::char_traits<char>; __istream_type = std::basic_istream<char>; __ios_type = std::basic_ios<char>]' (near match)
  126 |       operator>>(__ios_type& (*__pf)(__ios_type&))
      |       ^~~~~~~~
/usr/include/c++/14/istream:126:7: note:   conversion of argument 1 would be ill-formed:
a.cc:28:20: error: invalid conversion from 'long long int' to 'std::basic_istream<char>::__ios_type& (*)(std::basic_istream<char>::__ios_type&)' {aka 'std::basic_ios<char>& (*)(std::basic_ios<char>&)'} [-fpermissive]
   28 |         cin >> a[i]--;