Language: C++

#include <iostream>
#include <algorithm>
#include <utility>
#include <string>
#include <vector>
#include <set>
#include <stack>
#include <queue>
#include <map>
#include <math.h>
#include <string.h>
#include <iomanip>
#include <numeric>
#include <cstdlib>
#include <cstdint>
#include <cmath>
#include <functional>
#include <limits>
#include <cassert>
#include <bitset>
#include <atcoder/all>
 
using namespace std;
using namespace atcoder;
 
/* template */
 
using ll = long long;
using pll = pair<ll, ll>;
using vl = vector<ll>;
using vll = vector<vl>;
using vpll = vector<pll>;

void debug_out() { std::cout << std::endl; }
 
template <typename Head, typename... Tail>
void debug_out(Head H, Tail... T) {
  cout << H << " ";
  debug_out(T...);
}
 
#ifdef LOCAL
#define debug(...) cout << "debug: "; debug_out(__VA_ARGS__)
#else
#define debug(...) 
#endif
 
#define rep(i, a, n) for (int i = (int)(a); i < (int)(n); i++)
#define rrep(i, a, n) for (int i = ((int)(n-1)); i >= (int)(a); i--)
#define Rep(i, a, n) for (long long i = (long long)(a); i< (long long)(n); i++)
#define RRep(i, a, n) for (long long i = ((long long)(n-1ll)); i>=(long long)(a); i--)
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
 
template <typename T>
std::ostream& operator<<(std::ostream& os, std::vector<T> vec) {
  for (std::size_t i = 0; i < vec.size(); i++)os << vec[i] << (i + 1 == vec.size() ? "" : " ");
  return os;
}
 
struct Edge{
    int to;
    ll weight;
    Edge(int t, ll w) : to(t), weight(w){ }
};
 
struct edge{
    int from;
    int to;
    ll weight;
    edge(int f,int t,ll w) : from(f), to(t), weight(w){ }
};
 
using Graph = vector<vector<Edge>>;
using graph = vector<vector<int>>;
using edges = vector<edge>;

template <class T>
inline bool chmin(T &a, T b){
    if (a > b){
        a = b;
        return true;
    }
    return false;
}
 
template <class T>
inline bool chmax(T &a, T b){
    if (a < b){
        a = b;
        return true;
    }
    return false;
}
 
ll ctoi(char c) {
	switch (c) {
	case '0': return 0; case '1': return 1; case '2': return 2;
	case '3': return 3; case '4': return 4; case '5': return 5;
	case '6': return 6; case '7': return 7; case '8': return 8;
	case '9': return 9;  default: return 0;
	}
}
 
constexpr ll LNF = 1LL<<50;
 
constexpr int INF = 1e9+7;
 
const long double PI=acos(-1);

vector<int> dx = {1,0,-1,0};
vector<int> dy = {0,1,0,-1};

/* template */

//ax + by = gcd(a,b)を求める. 返り値はgcd(a,b)
ll extgcd(ll a, ll b, ll &x, ll &y){
    if(b==0){
        x = 1; y = 0;
        return a;
    }
    ll d = extgcd(b, a%b, y, x);
    y -= a/b * x;
    return d;
}

pair<ll,ll> ChineseRem(ll b1, ll m1, ll b2, ll m2){
    ll p,q;
    ll d = extgcd(m1,m2,p,q);
    if((b2-b1)%d != 0){
        return pair<ll,ll>(0,-1);
    }
    ll m = m1*(m2/d);
    ll tmp = (b2-b1)/d * p %(m2/d);
    ll r = b1+m1*tmp;
    r = (r%m + m)%m;
    return pair<ll,ll>(r,m);
}

int main(){
    cin.tie(nullptr);
    ios::sync_with_stdio(false);
    ll n; cin >> n;
    ll ans = LNF;
    n *= 2;
    for(ll i = 1; i*i<=n; i++){
        if(n%i==0){
            auto x = ChineseRem(0ll,i,-1,n/i);
            auto y = ChineseRem(0ll,n/i,-1,i);
            if(x.second>0){
                if(x.first == 0) x.first += x.second;
                chmin(ans,x.first);
            }
            if(y.second>0){
                if(y.first == 0) y.first += y.second;
                chmin(ans,y.first);
            }
        }
    }
    cout << ans << endl;
}


Compiler output:
a.cc:21:10: fatal error: atcoder/all: No such file or directory
   21 | #include <atcoder/all>
      |          ^~~~~~~~~~~~~
compilation terminated.