Submission #94400

#	Time	Username	Problem	Language	Result	Execution time	Memory
94400		qkxwsm	Mountain Trek Route (IZhO12_route)	C++14	0 / 100	742 ms	65832 KiB

route

#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

random_device(rd);
mt19937 rng(rd());
const long long FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();

struct custom_hash
{
	template<class T>
	unsigned long long operator()(T v) const
	{
		unsigned long long x = v;
		x += FIXED_RANDOM;
		// x += 11400714819323198485ull;
		// x = (x ^ (x >> 30)) * 13787848793156543929ull;
		x = (x ^ (x >> 27)) * 10723151780598845931ull;
		return x ^ (x >> 31);
	}
};

template<class T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<class T, class U> using hash_table = gp_hash_table<T, U, custom_hash>;

template<class T>
T randomize(T mod)
{
	return (uniform_int_distribution<T>(0, mod - 1))(rng);
}
template<class T>
void readi(T &x)
{
	x = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
	{
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		x = x * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		x = -x;
	}
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int buf[20], n = 0;
	while(output)
	{
		buf[n] = ((output % 10));
		output /= 10;
		n++;
	}
	for (n--; n >= 0; n--)
	{
		putchar(buf[n] + '0');
	}
	return;
}
template<class T>
void ckmin(T &a, T b)
{
	a = min(a, b);
}
template<class T>
void ckmax(T &a, T b)
{
	a = max(a, b);
}
long long expo(long long a, long long e, long long mod)
{
	return ((e == 0) ? 1 : ((expo(a * a % mod, e >> 1, mod)) * ((e & 1) ? a : 1) % mod));
}
template<class T, class U>
void nmod(T &x, U mod)
{
	if (x >= mod) x -= mod;
}
template<class T>
T gcd(T a, T b)
{
	return (b ? gcd(b, a % b) : a);
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define PB push_back
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define DBG(x) cerr << #x << " = " << (x) << endl
#define SZ(x) ((int) ((x).size()))
#define FOR(i, a, b) for (auto i = (a); i < (b); i++)
#define FORD(i, a, b) for (auto i = (a) - 1; i >= (b); i--)
#define ALL(x) (x).begin(), (x).end()

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-9;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<ld> vd;
typedef vector<pii> vpi;
typedef vector<pll> vpl;
typedef vector<pdd> vpd;

int N;
ll K;
vpl arr;
ll ans;

vpl clean(vpl vec)
{
	vpl res;
	FOR(i, 0, SZ(vec))
	{
		if (res.empty() || vec[i].fi != res.back().fi)
		{
			res.PB(vec[i]);
		}
		else
		{
			res.back().se += vec[i].se;
		}
	}
	return res;
}
pll go(int x)
{
	//# of moves, return!
	pll res = {0, 0};
	vpl cur;
	for (pll p : arr)
	{
		while(SZ(cur) >= 2)
		{
			pll q = cur.back(); cur.pop_back();
			if (q.fi > p.fi && q.fi > cur.back().fi && q.se <= x)
			{
				if (p.fi > cur.back().fi)
				{
					cur.PB({p.fi, q.se});
					res.fi += (q.fi - p.fi) * (q.se);
					res.se += (q.fi - p.fi);
				}
				else
				{
					cur.back().se += q.se;
					res.fi += (q.fi - cur.back().fi) * (q.se);
					res.se += (q.fi - cur.back().fi);
				}
			}
			else
			{
				cur.PB(q);
				break;
			}
		}
		if (cur.empty() || cur.back().fi != p.fi)
		{
			cur.PB(p);
		}
		else
		{
			cur.back().se += p.se;
		}
		// cerr << "cur contains:\n";
		// for (pll p : cur)
		// {
		// 	cerr << p.fi << ' ' << p.se << endl;
		// }
	}
	return res;
}

int32_t main()
{
	ios_base::sync_with_stdio(0); cin.tie(0);
	// cout << fixed << setprecision(10);
	// cerr << fixed << setprecision(10);
	// if (fopen("file.in", "r"))
	// {
	// 	freopen ("file.in", "r", stdin);
	// 	freopen ("file.out", "w", stdout);
	// }
	cin >> N >> K;
	FOR(i, 0, N)
	{
		ll x; cin >> x;
		arr.PB({x, 1});
	}
	ll mx = 0;
	FOR(i, 0, N)
	{
		if (arr[i].fi > arr[mx].fi)
		{
			mx = i;
		}
	}
	// DBG(mx);
	rotate(arr.begin(), arr.begin() + mx, arr.end());
	reverse(ALL(arr));
	// FOR(i, 0, N)
	// {
	// 	cerr << arr[i].fi << ' ';
	// }
	// cerr << endl;
	while(SZ(arr) > 1 && arr[SZ(arr) - 2].fi == arr[SZ(arr) - 1].fi)
	{
		arr.pop_back();
	}
	reverse(ALL(arr));
	mx = arr[0].fi;
	if (arr.back().fi == mx) arr.pop_back();
	FOR(i, 1, SZ(arr))
	{
		arr[i].fi = arr[0].fi - arr[i].fi;
	}
	arr[0].fi = 0;
	arr.PB({0, 1});
	// FOR(i, 0, SZ(arr))
	// {
	// 	cerr << arr[i].fi << ' ' << arr[i].se << endl;
	// }
	arr = clean(arr);
	// cerr << "original\n";
	// FOR(i, 0, SZ(arr))
	// {
	// 	cerr << arr[i].fi << ' ' << arr[i].se << endl;
	// }
	//binary serach on: we'll take moves that cost x, how long does it take us?
	pll p = go(N);
	if (p.fi < K)
	{
		cout << p.se * 2 << '\n';
		return 0;
	}
	ll lo = 1, hi = N;
	while(hi > lo)
	{
		int mid = (hi + lo) >> 1;
		pll p = go(mid);
		if (p.fi >= K) hi = mid;
		else lo = mid + 1;
	}
	p = go(lo);
	ans = 2 * (p.se - ((p.fi - K + lo - 1) / lo));
	cout << ans << '\n';
	// FOR(i, 0, N)
	// {
	// 	cerr << arr[i].fi << ' ';
	// }
	// cerr << endl;
	// cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}
/* READ READ READ
* int overflow, maxn too small, special cases (n=1?, two distinct?), cin.tie() interactive
* reread the problem, try small cases
* note down possible sources of error as you go
* do smth instead of nothing
*/

• Subtask 1: 0 / 100