tests/math/eea.test.cpp

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Last update: 2021-09-12 23:20:08-04:00
Problem: https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=NTL_1_E

Depends on

Code

#define PROBLEM "https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=NTL_1_E"
#include "../../template.hpp"
#include "../test_utils.hpp"
#include "../../math/eea.hpp"

int main() {
    fast_io();
    int a, b, x, y; cin >> a >> b;
    extgcd(a, b, x, y);
    print(x, y);
}

#line 1 "tests/math/eea.test.cpp"
#define PROBLEM "https://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=NTL_1_E"
#line 2 "template.hpp"
#include <bits/stdc++.h>
#define DEBUG 1
using namespace std;

// Defines
#define fs first
#define sn second
#define pb push_back
#define eb emplace_back
#define mpr make_pair
#define mtp make_tuple
#define all(x) (x).begin(), (x).end()
// Basic type definitions
#if __cplusplus == 201703L // CPP17 only things
template <typename T> using opt_ref = optional<reference_wrapper<T>>; // for some templates
#endif
using ll = long long; using ull = unsigned long long; using ld = long double;
using pii = pair<int, int>; using pll = pair<long long, long long>;
#ifdef __GNUG__
// PBDS order statistic tree
#include <ext/pb_ds/assoc_container.hpp> // Common file
#include <ext/pb_ds/tree_policy.hpp>
using namespace __gnu_pbds;
template <typename T, class comp = less<T>> using os_tree = tree<T, null_type, comp, rb_tree_tag, tree_order_statistics_node_update>;
template <typename K, typename V, class comp = less<K>> using treemap = tree<K, V, comp, rb_tree_tag, tree_order_statistics_node_update>;
// HashSet
#include <ext/pb_ds/assoc_container.hpp>
template <typename T, class Hash> using hashset = gp_hash_table<T, null_type, Hash>;
template <typename K, typename V, class Hash> using hashmap = gp_hash_table<K, V, Hash>;
const ll RANDOM = chrono::high_resolution_clock::now().time_since_epoch().count();
struct chash { ll operator()(ll x) const { return x ^ RANDOM; } };
#endif
// More utilities
int SZ(string &v) { return v.length(); }
template <typename C> int SZ(C &v) { return v.size(); }
template <typename C> void UNIQUE(vector<C> &v) { sort(v.begin(), v.end()); v.resize(unique(v.begin(), v.end()) - v.begin()); }
template <typename T, typename U> void maxa(T &a, U b) { a = max(a, b); }
template <typename T, typename U> void mina(T &a, U b) { a = min(a, b); }
const ll INF = 0x3f3f3f3f, LLINF = 0x3f3f3f3f3f3f3f3f;
#line 3 "tests/test_utils.hpp"

// I/O
template <typename T> void print(T v) {
    cout << v << '\n';
}

template <typename T, typename... Rest> void print(T v, Rest... vs) {
    cout << v << ' ';
    print(vs...);
}

void fast_io() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
}

// Reading operators
template <typename T, typename U> istream& operator>>(istream& in, pair<T, U> &o) {
    return in >> o.first >> o.second;
}

// Read helpers
int readi() {
    int x; cin >> x;
    return x;
}

ll readl() {
    ll x; cin >> x;
    return x;
}

template <typename T> vector<T> readv(int n) {
    vector<T> res(n);
    for (auto &x : res) cin >> x;
    return res;
}

// Functional stuff
template <typename T> vector<pair<int, T>> enumerate(vector<T> v, int start = 0) {
    vector<pair<int, T>> res;
    for (auto &x : v)
        res.emplace_back(start++, x);
    return res;
}

#line 3 "math/eea.hpp"

/*
 * ax + by = gcd(a, b)
 *
 * we know
 * bx' + (a%b)y' = gcd(a, b)
 *
 * bx' + (a-b*(a//b))y' = gcd(a, b)
 * bx' + ay' - b*(a//b)y' = gcd(a, b)
 * ay' + b(x' - (a//b)y') = gcd(a, b)
 */
template <typename T> T extgcd(T a, T b, T &x, T &y) {
    if (b == 0) {
        x = 1;
        y = 0;
        return a;
    }
    T x0, y0, res = extgcd(b, a%b, x0, y0);
    x = y0;
    y = x0 - (a / b) * y0;
    return res;
}
#line 5 "tests/math/eea.test.cpp"

int main() {
    fast_io();
    int a, b, x, y; cin >> a >> b;
    extgcd(a, b, x, y);
    print(x, y);
}