#include "bits/stdc++.h"
#pragma region template
using llint = long long;
using isize = std::ptrdiff_t;
using usize = std::size_t;
template <class T>
[[nodiscard]] inline T read() {
T ret;
std::cin >> ret;
return ret;
}
template <class T>
constexpr T floordiv(const T dividend, const T divisor) {
return (dividend + divisor - 1) / divisor;
}
template <class T>
auto mk_vec(const int n, const T value) {
return std::vector(n, value);
}
template <class... Args>
auto mk_vec(const int n, Args... args) {
return std::vector(n, mk_vec(args...));
}
template <class T, class = std::enable_if_t<std::is_signed_v<T>>>
class range {
struct range_iterator {
T itr;
constexpr range_iterator(const int pos) noexcept : itr(pos) {}
constexpr void operator++() noexcept { ++itr; }
constexpr bool operator!=(const range_iterator& other) const noexcept {
return itr != other.itr;
}
constexpr T operator*() const noexcept { return itr; }
};
public:
constexpr range(const T first_, const T last_) noexcept
: first(first_), last(last_) {}
constexpr range_iterator begin() const noexcept { return first; }
constexpr range_iterator end() const noexcept { return last; }
private:
const range_iterator first, last;
};
template <class T, class = std::enable_if_t<std::is_signed_v<T>>>
class revrange {
struct revrange_iterator {
T itr;
constexpr revrange_iterator(const int pos) noexcept : itr(pos) {}
constexpr void operator++() noexcept { --itr; }
constexpr bool operator!=(const revrange_iterator& other) const noexcept {
return itr != other.itr;
}
constexpr T operator*() const noexcept { return itr; }
};
public:
constexpr revrange(const T first_, const T last_) noexcept
: first(first_), last(last_ - 1) {}
constexpr revrange_iterator begin() const noexcept { return first; }
constexpr revrange_iterator end() const noexcept { return last; }
private:
const revrange_iterator first, last;
};
template <class F>
class rec_lambda {
public:
constexpr rec_lambda(F&& f_) : f(std::forward<F>(f_)) {}
template <class... Args>
constexpr auto operator()(Args&&... args) const {
return f(*this, std::forward<Args>(args)...);
}
private:
F f;
};
#pragma endregion
#ifdef _MSC_VER
// Sample program
constexpr std::array<llint, 4> sample = {2, 3, 6, 8};
constexpr int sampleN = 4;
void MinMax(llint s, llint t, llint& mn, llint& mx) {
const auto itr1 = std::lower_bound(sample.begin(), sample.end(), s);
const auto itr2 = std::upper_bound(sample.begin(), sample.end(), t);
if (itr1 == sample.end() or itr2 == sample.begin() or itr1 == itr2) {
mn = mx = -1;
return;
}
mn = *itr1;
mx = *(itr2 - 1);
}
#else
#include "gap.h"
#endif
llint findGap(int T, int N) {
/*
std::ios::sync_with_stdio(false);
std::cin.tie(nullptr);
*/
if (T == 1) {
// T = 1
std::vector<llint> A(N);
llint L = -1, R = 1ll << 62;
int cnt = 0;
while (cnt < ((N + 1) >> 1)) {
llint nxL, nxR;
#ifdef _MSC_VER
MinMax(L, R, nxL, nxR);
#else
MinMax(L, R, &nxL, &nxR);
#endif
if (nxL == -1 and nxR == -1) continue;
A[cnt] = nxL;
A[N - cnt - 1] = nxR;
++cnt;
L = ++nxL;
R = --nxR;
}
llint answer = 0;
for (int i : range(0, N - 1))
if (answer < A[i + 1] - A[i]) answer = A[i + 1] - A[i];
return answer;
} else {
llint L = -1, R = 1ll << 62;
#ifdef _MSC_VER
MinMax(L, R, L, R);
#else
MinMax(L, R, &L, &R);
#endif
llint min_width = (R - L) / N + ((R - L) % N == 0 ? 0 : 1);
// answer >= min_width
llint lastx = L;
llint ans = 0ll;
for (llint mn = L + 1, mx = L + min_width, cnt = 0; cnt < N;
mn += min_width, mx += min_width, ++cnt) {
llint mnr, mxr;
#ifdef _MSC_VER
MinMax(mn, mx, mnr, mxr);
#else
MinMax(mn, mx, &mnr, &mxr);
#endif
if (mnr == -1 and mxr == -1) continue;
if (ans < mnr - lastx) ans = mnr - lastx;
lastx = mxr;
}
if (ans < R - lastx) ans = R - lastx;
return ans;
}
}
