Buggy python submission (verdict: Runtime Error):
import sys
sys.setrecursionlimit(10**8)
class Scc:
    def __init__(self,n):
        self.n = n
        self.edges = []

    def add_edge(self,fr,to):
        assert 0 <= fr < self.n
        assert 0 <= to < self.n
        self.edges.append((fr, to))

    def scc(self):
        csr_start = [0] * (self.n + 1)
        csr_elist = [0] * len(self.edges)
        for fr,to in self.edges:
            csr_start[fr + 1] += 1
        for i in range(1,self.n+1):
            csr_start[i] += csr_start[i-1]
        counter = csr_start[:]
        for fr,to in self.edges:
            csr_elist[counter[fr]] = to
            counter[fr] += 1

        self.now_ord = self.group_num = 0
        self.visited = []
        self.low = [0] * self.n
        self.ord = [-1] * self.n
        self.ids = [0] * self.n
        def _dfs(v):
            self.low[v] = self.ord[v] = self.now_ord
            self.now_ord += 1
            self.visited.append(v)
            for i in range(csr_start[v], csr_start[v+1]):
                to = csr_elist[i]
                if self.ord[to] == -1:
                    _dfs(to)
                    self.low[v] = min(self.low[v], self.low[to])
                else:
                    self.low[v] = min(self.low[v], self.ord[to])
            if self.low[v] == self.ord[v]:
                while 1:
                    u = self.visited.pop()
                    self.ord[u] = self.n
                    self.ids[u] = self.group_num
                    if u==v: break
                self.group_num += 1
        for i in range(self.n):
            if self.ord[i] == -1: _dfs(i)
        for i in range(self.n):
            self.ids[i] = self.group_num - 1 - self.ids[i]

        groups = [[] for _ in range(self.group_num)]
        for i in range(self.n):
            groups[self.ids[i]].append(i)
        return groups

class TwoSat:
    def __init__(self,n=0):
        self.n = n
        self.answer = []
        self.scc = Scc(2*n)

    def add_clause(self, i:int, f:bool, j:int, g:bool):
        assert 0 <= i < self.n
        assert 0 <= j < self.n
        self.scc.add_edge(2*i + (not f), 2*j + g)
        self.scc.add_edge(2*j + (not g), 2*i + f)

    def satisfiable(self):
        g = self.scc.scc()
        for i in range(self.n):
            if self.scc.ids[2*i] == self.scc.ids[2*i+1]: return False
            self.answer.append(self.scc.ids[2*i] < self.scc.ids[2*i+1])
        return True

    def get_answer(self):
        return self.answer
N, K = map(int, input().split())
ts = TwoSat(N)
A = [int(input()) for _ in range(N)]
for i in range(1,N):
    if abs(A[i]-A[i-1]) <= K:
        ts.add_clause(A[i],True,A[i-1],True)
    else:
        ts.add_clause(A[i],False,A[i-1],False)
ts.satisfiable()
ans = 0
for i in ts.get_answer():
    if not i:
        ans += 1
print(ans)

Fixed submission:
def segfunc(x, y):
    return max(x, y)
ide_ele = -float('inf')

class SegTree:
    def __init__(self, init_val, segfunc, ide_ele):
        n = len(init_val)
        self.segfunc = segfunc
        self.ide_ele = ide_ele
        self.num = 1 << (n - 1).bit_length()
        self.tree = [ide_ele] * 2 * self.num
        for i in range(n):
            self.tree[self.num + i] = init_val[i]
        for i in range(self.num - 1, 0, -1):
            self.tree[i] = self.segfunc(self.tree[2 * i], self.tree[2 * i + 1])

    def update(self, k, x):
        k += self.num
        self.tree[k] = x
        while k > 1:
            self.tree[k >> 1] = self.segfunc(self.tree[k], self.tree[k ^ 1])
            k >>= 1

    def query(self, l, r):
        res = self.ide_ele

        l += self.num
        r += self.num
        while l < r:
            if l & 1:
                res = self.segfunc(res, self.tree[l])
                l += 1
            if r & 1:
                res = self.segfunc(res, self.tree[r - 1])
            l >>= 1
            r >>= 1
        return res

N, K = map(int, input().split())
A = [int(input()) for _ in range(N)]
max_v = max(A)
seg = SegTree([0]*max_v, segfunc, ide_ele)

for i in A:
    f = seg.query(max(0,i-K),min(max_v,i+K)+1)
    seg.update(i,f+1)

print(seg.query(0,max_v+1))