Problem:


Score : 400 points

Problem Statement

You are given a sequence A_1, A_2, ..., A_N and an integer K.

Print the maximum possible length of a sequence B that satisfies the following conditions:

B is a (not necessarily continuous) subsequence of A.

For each pair of adjacents elements of B, the absolute difference of the elements is at most K.

Constraints

1 \leq N \leq 300,000

0 \leq A_i \leq 300,000

0 \leq K \leq 300,000

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N K
A_1
A_2
:
A_N

Output

Print the answer.

Sample Input 1

10 3
1
5
4
3
8
6
9
7
2
4

Sample Output 1

7

For example, B = (1, 4, 3, 6, 9, 7, 4) satisfies the conditions.

It is a subsequence of A = (1, 5, 4, 3, 8, 6, 9, 7, 2, 4).

All of the absolute differences between two adjacent elements (|1-4|, |4-3|, |3-6|, |6-9|, |9-7|, |7-4|) are at most K = 3.



Sample input:
10 3
1
5
4
3
8
6
9
7
2
4


Sample output:
7

Submission status: Accepted

Solution code:
from typing import Callable, TypeVar, List

T = TypeVar('T')


class SegTree:
    def __init__(self, v: List[T], op: Callable[[T, T], T], e: Callable[[], T]) -> None:
        self._n = len(v)
        self.log = (self._n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [e for _ in range(2 * self.size)]
        self.op = op
        self.e = e
        for i in range(self._n):
            self.d[self.size + i] = v[i]
        for i in reversed(range(1, self.size)):
            self.__update__(i)

    @classmethod
    def init_e(cls, n: int, op: Callable[[T, T], T], e: Callable[[], T]) -> 'SegTree':
        return cls([e for _ in range(n)], op, e)

    def set(self, p: int, x: T) -> None:
        assert 0 <= p < self._n
        p += self.size
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.__update__(p >> i)

    def get(self, p: int) -> T:
        assert 0 <= p < self._n
        return self.d[p + self.size]

    def prod(self, l: int, r: int) -> T:
        assert 0 <= l <= self._n and 0 <= r <= self._n
        sml = self.e
        smr = self.e
        l += self.size
        r += self.size

        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self) -> T:
        return self.d[1]

    def max_right(self, l: int, f: Callable[[T], bool]):
        assert 0 <= l <= self._n
        assert f(self.e)
        if l == self._n:
            return self._n
        l += self.size
        sm = self.e
        while True:
            while l % 2 == 0:
                l >>= 1
            if not f(self.op(sm, self.d[l])):
                while l < self.size:
                    l *= 2
                    if f(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l:
                return self._n

    def min_left(self, r: int, f: Callable[[T], bool]):
        assert 0 <= r <= self._n
        assert f(self.e)
        if r == 0:
            return 0
        r += self.size
        sm = self.e
        while True:
            r -= 1
            while r > 1 and r % 2:
                r >>= 1
            if not f(self.op(self.d[r], sm)):
                while r < self.size:
                    r = 2 * r + 1
                    if f(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r:
                return 0

    def __update__(self, k: int) -> None:
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])


n, k = map(int, input().split())
seg = SegTree([0]*400000, max, 0)
for _ in range(n):
    a = int(input())
    ma = seg.prod(max(0, a-k), min(400000, a+k+1))
    seg.set(a, ma+1)
print(seg.all_prod())

Submission status: Accepted

Solution code:
from typing import Callable, TypeVar, List

T = TypeVar('T')


class SegTree:
    def __init__(self, v: List[T], op: Callable[[T, T], T], e: Callable[[], T]) -> None:
        self._n = len(v)
        self.log = (self._n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [e() for _ in range(2 * self.size)]
        self.op = op
        self.e = e
        for i in range(self._n):
            self.d[self.size + i] = v[i]
        for i in reversed(range(1, self.size)):
            self.__update__(i)

    @classmethod
    def init_e(cls, n: int, op: Callable[[T, T], T], e: Callable[[], T]) -> 'SegTree':
        return cls([e() for _ in range(n)], op, e)

    def set(self, p: int, x: T) -> None:
        p += self.size
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.__update__(p >> i)

    def get(self, p: int) -> T:
        return self.d[p + self.size]

    def prod(self, l: int, r: int) -> T:
        sml = self.e()
        smr = self.e()
        l += self.size
        r += self.size

        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self) -> T:
        return self.d[1]

    def max_right(self, l: int, f: Callable[[T], bool]):
        if l == self._n:
            return self._n
        l += self.size
        sm = self.e()
        while True:
            while l % 2 == 0:
                l >>= 1
            if not f(self.op(sm, self.d[l])):
                while l < self.size:
                    l *= 2
                    if f(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l:
                return self._n

    def min_left(self, r: int, f: Callable[[T], bool]):
        assert 0 <= r <= self._n
        assert f(self.e())
        if r == 0:
            return 0
        r += self.size
        sm = self.e()
        while True:
            r -= 1
            while r > 1 and r % 2:
                r >>= 1
            if not f(self.op(self.d[r], sm)):
                while r < self.size:
                    r = 2 * r + 1
                    if f(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r:
                return 0

    def __update__(self, k: int) -> None:
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])


n, k = map(int, input().split())
seg = SegTree([0]*400000, max, lambda: 0)
for _ in range(n):
    a = int(input())
    ma = seg.prod(max(0, a-k), min(400000, a+k+1))
    seg.set(a, ma+1)
print(seg.all_prod())

Submission status: Accepted

Solution code:
code = r"""
# distutils: language=c++
# distutils: include_dirs=/opt/ac-library
from libcpp cimport bool
from libcpp.vector cimport vector
cdef extern from "<atcoder/segtree>" namespace "atcoder" nogil:
    cdef cppclass segtree[S, OP, E]:
        segtree(vector[S] v)
        void set(int p, S x)
        S get(int p)
        S prod(int l, int r)
        S all_prod()
        int max_right[F](int l)
        int min_left[F](int r)
ctypedef long seg_t
cdef extern from *:
    ctypedef int op_t "myop"
    ctypedef int e_t "mye"
    ctypedef int f_t "myf"
    cdef seg_t myop(seg_t a, seg_t b) nogil
    cdef seg_t mye() nogil
    cdef bool myf(seg_t k) nogil
cdef seg_t myop(seg_t a, seg_t b) nogil:
    if a > b:
        return a
    else:
        return b
cdef seg_t mye() nogil:
    return 0
cdef seg_t v
cdef bool myf(seg_t k) nogil:
    return k < v

from cython.parallel cimport prange
from libc.stdio cimport getchar, printf
cdef inline long read() nogil:
    cdef long b, c = 0
    while 1:
        b = getchar() - 48
        if b < 0: return c
        c = c * 10 + b
cdef main():
    cdef long n = read(), k = read(), i
    cdef seg_t a
    cdef segtree[seg_t, op_t, e_t] *seg = new segtree[seg_t, op_t, e_t](vector[seg_t](600001, 0))
    for i in range(n):
        a = read()
        seg.set(a, seg.prod(myop(0, a - k), a + k + 1) + 1)
    printf('%ld\n', seg.all_prod())
main()
"""
import os, sys
if sys.argv[-1] == 'ONLINE_JUDGE':
    open('solve.pyx', 'w').write(code)
    os.system('cythonize -i -3 -b solve.pyx')
import solve

Submission status: Accepted

Solution code:
from typing import Callable, TypeVar, List

T = TypeVar('T')


class SegTree:
    def __init__(self, v: List[T], op: Callable[[T, T], T], e: Callable[[], T]) -> None:
        self._n = len(v)
        self.log = (self._n - 1).bit_length()
        self.size = 1 << self.log
        self.d = [e() for _ in range(2 * self.size)]
        self.op = op
        self.e = e
        for i in range(self._n):
            self.d[self.size + i] = v[i]
        for i in reversed(range(1, self.size)):
            self.__update__(i)

    @classmethod
    def init_e(cls, n: int, op: Callable[[T, T], T], e: Callable[[], T]) -> 'SegTree':
        return cls([e() for _ in range(n)], op, e)

    def set(self, p: int, x: T) -> None:
        assert 0 <= p < self._n
        p += self.size
        self.d[p] = x
        for i in range(1, self.log + 1):
            self.__update__(p >> i)

    def get(self, p: int) -> T:
        assert 0 <= p < self._n
        return self.d[p + self.size]

    def prod(self, l: int, r: int) -> T:
        assert 0 <= l <= self._n and 0 <= r <= self._n
        sml = self.e()
        smr = self.e()
        l += self.size
        r += self.size

        while l < r:
            if l & 1:
                sml = self.op(sml, self.d[l])
                l += 1
            if r & 1:
                r -= 1
                smr = self.op(self.d[r], smr)
            l >>= 1
            r >>= 1
        return self.op(sml, smr)

    def all_prod(self) -> T:
        return self.d[1]

    def max_right(self, l: int, f: Callable[[T], bool]):
        assert 0 <= l <= self._n
        assert f(self.e())
        if l == self._n:
            return self._n
        l += self.size
        sm = self.e()
        while True:
            while l % 2 == 0:
                l >>= 1
            if not f(self.op(sm, self.d[l])):
                while l < self.size:
                    l *= 2
                    if f(self.op(sm, self.d[l])):
                        sm = self.op(sm, self.d[l])
                        l += 1
                return l - self.size
            sm = self.op(sm, self.d[l])
            l += 1
            if (l & -l) == l:
                return self._n

    def min_left(self, r: int, f: Callable[[T], bool]):
        assert 0 <= r <= self._n
        assert f(self.e())
        if r == 0:
            return 0
        r += self.size
        sm = self.e()
        while True:
            r -= 1
            while r > 1 and r % 2:
                r >>= 1
            if not f(self.op(self.d[r], sm)):
                while r < self.size:
                    r = 2 * r + 1
                    if f(self.op(self.d[r], sm)):
                        sm = self.op(self.d[r], sm)
                        r -= 1
                return r + 1 - self.size
            sm = self.op(self.d[r], sm)
            if (r & -r) == r:
                return 0

    def __update__(self, k: int) -> None:
        self.d[k] = self.op(self.d[2 * k], self.d[2 * k + 1])


n, k = map(int, input().split())
seg = SegTree([0]*400000, max, lambda: 0)
for _ in range(n):
    a = int(input())
    ma = seg.prod(max(0, a-k), min(400000, a+k+1))
    seg.set(a, ma+1)
print(seg.all_prod())

Submission status: Accepted

Solution code:

import sys
# sys.setrecursionlimit(100000)


def input():
    return sys.stdin.readline().strip()


def input_int():
    return int(input())


def input_int_list():
    return [int(i) for i in input().split()]


class SegTree:
    X_unit = 0
    X_f = max

    def __init__(self, N):
        self.N = N
        self.X = [self.X_unit] * (N + N)

    def build(self, seq):
        for i, x in enumerate(seq, self.N):
            self.X[i] = x
        for i in range(self.N - 1, 0, -1):
            self.X[i] = self.X_f(self.X[i << 1], self.X[i << 1 | 1])

    def set_val(self, i, x):
        i += self.N
        self.X[i] = x
        while i > 1:
            i >>= 1
            self.X[i] = self.X_f(self.X[i << 1], self.X[i << 1 | 1])

    def fold(self, L, R):
        L += self.N
        R += self.N
        vL = self.X_unit
        vR = self.X_unit
        while L < R:
            if L & 1:
                vL = self.X_f(vL, self.X[L])
                L += 1
            if R & 1:
                R -= 1
                vR = self.X_f(self.X[R], vR)
            L >>= 1
            R >>= 1
        return self.X_f(vL, vR)


def main():
    n, k = input_int_list()
    segtree = SegTree(300001)
    for _ in range(n):
        a = input_int()

        val = segtree.fold(max(0, a - k), min(300001, a + k + 1))
        segtree.set_val(a, val + 1)

    print(segtree.X[1])

    return


if __name__ == "__main__":
    main()

Submission status: Accepted

Solution code:
# でつoO(YOU PLAY WITH THE CARDS YOU'RE DEALT..)
import sys
def main(N, K, A):
    tree = SegmentTree(300_300)
    for a in A:
        p = tree.query(max(0, a - K), min(300_300, a + K + 1))
        tree.modify(a, p + 1)
    print(tree.query_all())

class SegmentTree:
    __slots__ = ('__n', '__d', '__f', '__e')

    def __init__(self, n=None, f=max, identity_factory=int, initial_values=None):
        assert(n or initial_values)
        size = n if n else len(initial_values)
        d = [identity_factory() for _ in range(2 * size + 1)]
        self.__n, self.__d, self.__f, self.__e = size, d, f, identity_factory
        if initial_values:
            for i, v in enumerate(initial_values): d[size + i] = v
            for i in range(size - 1, 0, -1): d[i] = f(d[i << 1], d[i << 1 | 1])

    def get_val(self, index):
        return self.__d[index + self.__n]

    def set_val(self, index, new_value):
        i, d, f = index + self.__n, self.__d, self.__f
        if d[i] == new_value: return
        d[i], i = new_value, i >> 1
        while i: d[i], i = f(d[i << 1], d[i << 1 | 1]), i >> 1

    def modify(self, index, value):
        self.set_val(index, self.__f(self.__d[index + self.__n], value))

    def query(self, from_inclusive, to_exclusive):
        ans = self.__e()
        if to_exclusive <= from_inclusive: return ans
        l, r, d, f = from_inclusive + self.__n, to_exclusive + self.__n, self.__d, self.__f
        while l < r:
            if l & 1: ans, l = f(ans, d[l]), l + 1
            if r & 1: ans, r = f(d[r - 1], ans), r - 1
            l, r = l >> 1, r >> 1
        return ans

    def query_all(self):
        return self.__d[1]

    def bisect_left(self, func):
        '''func()がFalseになるもっとも左のindexを探す
        '''
        i, j, n, f, d, v = self.__n, self.__n + self.__n, self.__n, self.__f, self.__d, self.__e()
        while i < j:
            if i & 1:
                nv = f(v, d[i])
                if not func(nv): break
                v, i = nv, i + 1
            i, j = i >> 1, j >> 1
        while i < n:
            nv = f(v, d[i << 1])
            if func(nv): v, i = nv, i << 1 | 1
            else: i = i << 1
        return i - n

if __name__ == '__main__':
    input = sys.stdin.readline
    N, K = map(int, input().split())
    A = [int(input()) for _ in range(N)]
    main(N, K, A)