Buggy python submission (verdict: Runtime Error):
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = 300010
    
    ll = - 10 ** 10    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [0]*(2*N0)
    lazy = [ll]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v == ll:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = max(v, lazy[2*i-1], data[2*i-1], lazy[2*i], data[2*i])
            lazy[i-1] = ll
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                lazy[R-1] = data[R-1] = max(lazy[R-1], data[R-1], x)
            if L & 1:
                lazy[L-1] = data[L-1] = max(lazy[L-1], data[L-1], x)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = 0
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        l = a - k
        r = a + k
        xx = query(a, a + 1) + 1
        update(l, r + 1, xx)
        ans = max(ans, xx)
    print(ans)
    
main()


Fixed submission:
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = 300100
    
    ll = - 10 ** 10    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [0]*(2*N0)
    lazy = [ll]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v == ll:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = max(v, data[2*i-1], data[2*i])
            lazy[i-1] = ll
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                lazy[R-1] = data[R-1] = max(data[R-1], x)
            if L & 1:
                lazy[L-1] = data[L-1] = max(data[L-1], x)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = 0
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        a += 50
        l = max(0,a - k)
        r = min(a + k, 300099)
        xx = query(l, r + 1) + 1
        update(a, a + 1, xx)
        ans = max(ans, xx)
    print(ans)
    
main()

Buggy python submission (verdict: Runtime Error):
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = max(alst) + 1
    
    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [0]*(2*N0)
    lazy = [0]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v == 0:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = v
            lazy[i-1] = 0
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                lazy[R-1] = data[R-1] = max(lazy[R-1], data[R-1], x)
            if L & 1:
                lazy[L-1] = data[L-1] = max(lazy[R-1], data[L-1], x)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = 0
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        l = a - k
        r = a + k
        x = query(a, a + 1) + 1
        update(l, r + 1, x)
        ans = max(ans, x)
    print(ans)
    
main()


Fixed submission:
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = 300100
    
    ll = - 10 ** 10    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [0]*(2*N0)
    lazy = [ll]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v == ll:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = max(v, data[2*i-1], data[2*i])
            lazy[i-1] = ll
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                lazy[R-1] = data[R-1] = max(data[R-1], x)
            if L & 1:
                lazy[L-1] = data[L-1] = max(data[L-1], x)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = 0
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        a += 50
        l = max(0,a - k)
        r = min(a + k, 300099)
        xx = query(l, r + 1) + 1
        update(a, a + 1, xx)
        ans = max(ans, xx)
    print(ans)
    
main()

Buggy python submission (verdict: Runtime Error):
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = max(alst) + 1
    
    INF = 0
    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [INF]*(2*N0)
    lazy = [None]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v is None:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = v
            lazy[i-1] = None
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                xx = max(data[R-1], x)
                if lazy[R-1] != None:
                    xx = max(xx, lazy[R-1])
                lazy[R-1] = data[R-1] = max(data[R-1], xx)
            if L & 1:
                xx = max(data[R-1], x)
                if lazy[L-1] != None:
                    xx = max(xx, lazy[L-1])
                lazy[L-1] = data[L-1] = max(data[L-1], xx)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = INF
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        l = a - k
        r = a + k
        x = query(a, a + 1) + 1
        update(l, r + 1, x)
        ans = max(ans, x)
    print(ans)
    
main()

Fixed submission:
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = 300100
    
    ll = - 10 ** 10    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [0]*(2*N0)
    lazy = [ll]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v == ll:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = max(v, data[2*i-1], data[2*i])
            lazy[i-1] = ll
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                lazy[R-1] = data[R-1] = max(data[R-1], x)
            if L & 1:
                lazy[L-1] = data[L-1] = max(data[L-1], x)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = 0
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        a += 50
        l = max(0,a - k)
        r = min(a + k, 300099)
        xx = query(l, r + 1) + 1
        update(a, a + 1, xx)
        ans = max(ans, xx)
    print(ans)
    
main()

Buggy python submission (verdict: Runtime Error):
N, k = map(int, input().split())
alst = [int(input()) for _ in range(N)]

INF = 0

LV = (N-1).bit_length()
N0 = 2**LV
data = [INF]*(2*N0)
lazy = [None]*(2*N0)

def gindex(l, r):
    L = (l + N0) >> 1; R = (r + N0) >> 1
    lc = 0 if l & 1 else (L & -L).bit_length()
    rc = 0 if r & 1 else (R & -R).bit_length()
    for i in range(LV):
        if rc <= i:
            yield R
        if L < R and lc <= i:
            yield L
        L >>= 1; R >>= 1

def propagates(*ids):
    for i in reversed(ids):
        v = lazy[i-1]
        if v is None:
            continue
        lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = v
        lazy[i-1] = None

def update(l, r, x):
    *ids, = gindex(l, r)
    propagates(*ids)

    L = N0 + l; R = N0 + r
    while L < R:
        if R & 1:
            R -= 1
            lazy[R-1] = data[R-1] = max(data[R-1], x)
        if L & 1:
            lazy[L-1] = data[L-1] = max(data[L-1], x)
            L += 1
        L >>= 1; R >>= 1
    for i in ids:
        data[i-1] = max(data[2*i-1], data[2*i])

def query(l, r):
    propagates(*gindex(l, r))
    L = N0 + l; R = N0 + r

    s = INF
    while L < R:
        if R & 1:
            R -= 1
            s = max(s, data[R-1])
        if L & 1:
            s = max(s, data[L-1])
            L += 1
        L >>= 1; R >>= 1
    return s

ans = 0
for a in alst:
    l = max(0, a - k)
    r = min(N - 1, a + k)
    x = query(a, a + 1) + 1
    update(l, r + 1, x)
    ans = max(ans, x)
    
print(ans)

Fixed submission:
import sys
input = sys.stdin.readline

def main():
    n, k = map(int, input().split())
    alst = [int(input()) for _ in range(n)]
    N = 300100
    
    ll = - 10 ** 10    
    LV = (N-1).bit_length()
    N0 = 2**LV
    data = [0]*(2*N0)
    lazy = [ll]*(2*N0)
    
    def gindex(l, r):
        L = (l + N0) >> 1; R = (r + N0) >> 1
        lc = 0 if l & 1 else (L & -L).bit_length()
        rc = 0 if r & 1 else (R & -R).bit_length()
        for i in range(LV):
            if rc <= i:
                yield R
            if L < R and lc <= i:
                yield L
            L >>= 1; R >>= 1
    
    def propagates(*ids):
        for i in reversed(ids):
            v = lazy[i-1]
            if v == ll:
                continue
            lazy[2*i-1] = data[2*i-1] = lazy[2*i] = data[2*i] = max(v, data[2*i-1], data[2*i])
            lazy[i-1] = ll
    
    def update(l, r, x):
        *ids, = gindex(l, r)
        propagates(*ids)
    
        L = N0 + l; R = N0 + r
        while L < R:
            if R & 1:
                R -= 1
                lazy[R-1] = data[R-1] = max(data[R-1], x)
            if L & 1:
                lazy[L-1] = data[L-1] = max(data[L-1], x)
                L += 1
            L >>= 1; R >>= 1
        for i in ids:
            data[i-1] = max(data[2*i-1], data[2*i])
    
    def query(l, r):
        propagates(*gindex(l, r))
        L = N0 + l; R = N0 + r
    
        s = 0
        while L < R:
            if R & 1:
                R -= 1
                s = max(s, data[R-1])
            if L & 1:
                s = max(s, data[L-1])
                L += 1
            L >>= 1; R >>= 1
        return s
    
    ans = 0
    for a in alst:
        a += 50
        l = max(0,a - k)
        r = min(a + k, 300099)
        xx = query(l, r + 1) + 1
        update(a, a + 1, xx)
        ans = max(ans, xx)
    print(ans)
    
main()