test/yosupo/Math/Sum-of-Floor-of-Linear.test.cpp

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Last update: 2023-11-11 17:58:53+09:00
Problem: https://judge.yosupo.jp/problem/sum_of_floor_of_linear

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Code

#define PROBLEM "https://judge.yosupo.jp/problem/sum_of_floor_of_linear"

#include "../../../template/template.hpp"

#include "../../../math/floor-sum.hpp"

int main(){
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  int t;
  cin >> t;
  rep(_, t){
    int n,m,a,b;
    cin >> n >> m >> a >> b;
    cout << floor_sum(n, m, a, b) << "\n";
  }
}

#line 1 "test/yosupo/Math/Sum-of-Floor-of-Linear.test.cpp"
#define PROBLEM "https://judge.yosupo.jp/problem/sum_of_floor_of_linear"

#line 1 "template/template.hpp"
#include <iostream>
#include <cmath>
#include <string>
#include <vector>
#include <algorithm>
#include <tuple>
#include <cstdint>
#include <cstdio>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <deque>
#include <bitset>
#include <cctype>
#include <climits>
#include <functional>
#include <cassert>
#include <numeric>
#include <cstring>
#define rep(i, n) for(int i = 0; i < (n); i++)
#define per(i, n) for(int i = (n) - 1; i >= 0; i--)
using ll = long long;
#define vi vector<int>
#define vvi vector<vi>
#define vl vector<ll>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
constexpr int mod = 1000000007;
using namespace std;
template<class T, class U>
bool chmax(T &a, const U &b){ return a < b ? (a = b, 1) : 0; }
template<class T, class U>
bool chmin(T &a, const U &b){ return a > b ? (a = b, 1) : 0; }
#line 4 "test/yosupo/Math/Sum-of-Floor-of-Linear.test.cpp"

#line 1 "math/floor-sum.hpp"
using ull = unsigned long long;

ull floor_sum_unsigned(ull n, ull m, ull a, ull b){
  ull ans = 0;
  while(true){
    if(a >= m){
      ans += n * (n - 1) / 2 * (a / m);
      a %= m;
    }
    if(b >= m){
      ans += n * (b / m);
      b %= m;
    }
    const ull y_max = a * n + b;
    if(y_max < m) break;
    n = y_max / m;
    b = y_max % m;
    swap(m, a);
  }
  return ans;
}
ll floor_sum(const ll n, const ll m, ll a, ll b){
  assert(0 <= n && n < (1LL << 32));
  assert(1 <= m && m < (1LL << 32));
  ull ans = 0;
  if(a < 0){
    const ull a2 = (a % m + m) % m;
    ans -= 1ULL * n * (n - 1) / 2 * ((a2 - a) / m);
    a = a2;
  }
  if(b < 0){
    const ull b2 = (b % m + m) % m;
    ans -= 1ULL * n * ((b2 - b) / m);
    b = b2;
  }
  return ans + floor_sum_unsigned(n, m, a, b);
}
#line 6 "test/yosupo/Math/Sum-of-Floor-of-Linear.test.cpp"

int main(){
  cin.tie(nullptr);
  ios_base::sync_with_stdio(false);
  int t;
  cin >> t;
  rep(_, t){
    int n,m,a,b;
    cin >> n >> m >> a >> b;
    cout << floor_sum(n, m, a, b) << "\n";
  }
}