Submission #71046

#	Time	Username	Problem	Language	Result	Execution time	Memory
71046		qkxwsm	Global Warming (CEOI18_glo)	C++17	100 / 100	195 ms	4744 KiB

glo

/*
PROG: source
LANG: C++11
    _____
  .'     '.
 /  0   0  \
|     ^     |
|  \     /  |
 \  '---'  /
  '._____.'
*/
#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>

using namespace std;
using namespace __gnu_pbds;

struct chash
{
        int operator()(int x) const
        {
                x ^= (x >> 20) ^ (x >> 12);
                return x ^ (x >> 7) ^ (x >> 4);
        }
        int operator()(long long x) const
        {
                return x ^ (x >> 32);
        }
};

template<typename T> using orderedset = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
template<typename T, typename U> using hashtable = gp_hash_table<T, U, chash>;

template<class T>
void readi(T &x)
{
	T input = 0;
	bool negative = false;
	char c = ' ';
	while (c < '-')
        {
		c = getchar();
	}
	if (c == '-')
	{
		negative = true;
		c = getchar();
	}
	while (c >= '0')
	{
		input = input * 10 + (c - '0');
		c = getchar();
	}
	if (negative)
	{
		input = -input;
	}
	x = input;
}
template<class T>
void printi(T output)
{
	if (output == 0)
	{
		putchar('0');
		return;
	}
	if (output < 0)
	{
		putchar('-');
		output = -output;
	}
	int aout[20];
	int ilen = 0;
	while(output)
	{
		aout[ilen] = ((output % 10));
		output /= 10;
		ilen++;
	}
	for (int i = ilen - 1; i >= 0; i--)
	{
		putchar(aout[i] + '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);
}
template<class T, class U>
T normalize(T x, U mod = 1000000007)
{
	return (((x % mod) + mod) % mod);
}
long long randomizell(long long mod)
{
	return ((1ll << 45) * rand() + (1ll << 30) * rand() + (1ll << 15) * rand() + rand()) % mod;
}
int randomize(int mod)
{
	return ((1ll << 15) * rand() + rand()) % mod;
}

#define y0 ___y0
#define y1 ___y1
#define MP make_pair
#define MT make_tuple
#define PB push_back
#define PF push_front
#define LB lower_bound
#define UB upper_bound
#define fi first
#define se second
#define debug(x) cerr << #x << " = " << x << endl;

const long double PI = 4.0 * atan(1.0);
const long double EPS = 1e-10;

#define MAGIC 347
#define SINF 10007
#define CO 1000007
#define INF 1000000007
#define BIG 1000000931
#define LARGE 1696969696967ll
#define GIANT 2564008813937411ll
#define LLINF 2696969696969696969ll
#define MAXN 200013

typedef long long ll;
typedef long double ld;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
typedef pair<ld, ld> pdd;

int N;
int X;
int arr[MAXN];
int pref[MAXN];
int fw[MAXN], bw[MAXN];
int fen[MAXN];
vector<int> compress;
int ans;

void update(int idx, int v)
{
        for (int e = idx + 1; e <= N + 2; e += e & (-e))
        {
                ckmax(fen[e], v);
        }
        return;
}
int query(int idx)
{
        int res = 0;
        for (int e = idx + 1; e > 0; e -= e & (-e))
        {
                ckmax(res, fen[e]);
        }
        return res;
}
int getindex(int x)
{
        return LB(compress.begin(), compress.end(), x) - compress.begin();
}

int32_t main()
{
	ios_base::sync_with_stdio(0);
	srand(time(0));
	//	cout << fixed << setprecision(10);
	//	cerr << fixed << setprecision(10);
	if (fopen("input.in", "r"))
	{
		freopen ("input.in", "r", stdin);
		freopen ("output.out", "w", stdout);
	}
        cin >> N >> X;
        for (int i = 0; i < N; i++)
        {
                cin >> arr[i];
                compress.PB(arr[i]);
        }
        sort(compress.begin(), compress.end());
        compress.erase(unique(compress.begin(), compress.end()), compress.end());
        //you only want to change prefixes
        for (int i = 0; i <= N + 2; i++)
        {
                fen[i] = 0;
        }
        for (int i = N - 1; i >= 0; i--)
        {
                int idx = getindex(arr[i]);
                bw[i] = query(N - idx - 2) + 1;
                update(N - idx - 1, bw[i]);
                ckmax(ans, bw[i]);
        }
        for (int i = 0; i <= N + 2; i++)
        {
                fen[i] = 0;
        }
        for (int i = 0; i < N; i++)
        {
                int idx = getindex(arr[i]);
                fw[i] = query(idx - 1) + 1;
                update(idx, fw[i]);
                ckmax(ans, fw[i]);
                if (i != N - 1)
                {
                        idx = getindex(arr[i + 1] + X);
                        ckmax(ans, bw[i + 1] + query(idx - 1));
                }
        }
        //can you make the LIS at least j?
        cout << ans << '\n';
	//	cerr << "time elapsed = " << (clock() / (CLOCKS_PER_SEC / 1000)) << " ms" << endl;
	return 0;
}

Compilation message (stderr)

glo.cpp: In function 'int32_t main()':
glo.cpp:182:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("input.in", "r", stdin);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
glo.cpp:183:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   freopen ("output.out", "w", stdout);
   ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 10 / 10
• Subtask 3: 13 / 13
• Subtask 4: 10 / 10
• Subtask 5: 20 / 20
• Subtask 6: 17 / 17
• Subtask 7: 25 / 25