Buggy python submission (verdict: Runtime Error):
# seishin.py
N = int(input())
*X, = map(int, input().split())
L = int(input())

K = N.bit_length()

D = [[-1] for i in range(N)]
j = N-1
for i in range(N-1, -1, -1):
    while j > 0 and X[j] - X[i] > L:
        j -= 1
    D[i][0] = j
v = 2
for k in range(K):
    for i in range(N-v):
        if i + v < N and len(D[D[i][k]]) == k+1:
            D[i].append(D[D[i][k]][k])
    v <<= 1
def solve(a, b):
    if not a < b:
        a, b = b, a
    res = 1
    v = 2**K
    for k in range(K, -1, -1):
        if a + v < N-1 and D[a][k] < b:
            a = D[a][k]
            res += v
        v >>= 1
    return res
Q = int(input())
ans = []
for i in range(Q):
    a, b = map(int, input().split())
    ans.append(solve(a-1, b-1))
print(*ans, sep='\n')


Fixed submission:
# seishin.py
N = int(input())
*X, = map(int, input().split())
L = int(input())

K = 20

D = [[N]*(K+1) for i in range(N)]
j = N-1
for i in range(N-1, -1, -1):
    while j > 0 and X[j] - X[i] > L:
        j -= 1
    D[i][0] = j
for k in range(K):
    for i in range(N):
        if D[i][k] != N:
            D[i][k+1] = D[D[i][k]][k]
def solve(a, b):
    if not a < b:
        a, b = b, a
    res = 1
    for k in range(K, -1, -1):
        if D[a][k] < b:
            a = D[a][k]
            res += 2**k
    return res
Q = int(input())
ans = []
for i in range(Q):
    a, b = map(int, input().split())
    ans.append(solve(a-1, b-1))
print(*ans, sep='\n')

Buggy python submission (verdict: Time Limit Exceeded):
# seishin.py
N = int(input())
*X, = map(int, input().split())
L = int(input())

K = 318

D = {}
j = N-1
for i in range(N-1, -1, -1):
    while j > 0 and X[j] - X[i] > L:
        j -= 1
    D[i, 0] = j
for k in range(K):
    for i in range(N):
        if (i, k) in D and (D[i, k], k) in D:
            D[i, k+1] = D[D[i, k], k]
def solve(a, b):
    if not a < b:
        a, b = b, a
    res = 1
    for k in range(K, -1, -1):
        if D.get((a, k), N) < b:
            a = D[a, k]
            res += 2**k
    return res
Q = int(input())
ans = []
for i in range(Q):
    a, b = map(int, input().split())
    ans.append(solve(a-1, b-1))
print(*ans, sep='\n')


Fixed submission:
# seishin.py
N = int(input())
*X, = map(int, input().split())
L = int(input())

K = 20

D = [[N]*(K+1) for i in range(N)]
j = N-1
for i in range(N-1, -1, -1):
    while j > 0 and X[j] - X[i] > L:
        j -= 1
    D[i][0] = j
for k in range(K):
    for i in range(N):
        if D[i][k] != N:
            D[i][k+1] = D[D[i][k]][k]
def solve(a, b):
    if not a < b:
        a, b = b, a
    res = 1
    for k in range(K, -1, -1):
        if D[a][k] < b:
            a = D[a][k]
            res += 2**k
    return res
Q = int(input())
ans = []
for i in range(Q):
    a, b = map(int, input().split())
    ans.append(solve(a-1, b-1))
print(*ans, sep='\n')

Buggy python submission (verdict: Time Limit Exceeded):
# seishin.py
N = int(input())
*X, = map(int, input().split())
L = int(input())

K = 318

D = [[N]*(K+1) for i in range(N)]
j = N-1
for i in range(N-1, -1, -1):
    while j > 0 and X[j] - X[i] > L:
        j -= 1
    D[i][0] = j
for k in range(K):
    for i in range(N):
        if D[i][k] != N:
            D[i][k+1] = D[D[i][k]][k]
def solve(a, b):
    if not a < b:
        a, b = b, a
    res = 1
    for k in range(K, -1, -1):
        if D[a][k] < b:
            a = D[a][k]
            res += 2**k
    return res
Q = int(input())
ans = []
for i in range(Q):
    a, b = map(int, input().split())
    ans.append(solve(a-1, b-1))
print(*ans, sep='\n')

Fixed submission:
# seishin.py
N = int(input())
*X, = map(int, input().split())
L = int(input())

K = 20

D = [[N]*(K+1) for i in range(N)]
j = N-1
for i in range(N-1, -1, -1):
    while j > 0 and X[j] - X[i] > L:
        j -= 1
    D[i][0] = j
for k in range(K):
    for i in range(N):
        if D[i][k] != N:
            D[i][k+1] = D[D[i][k]][k]
def solve(a, b):
    if not a < b:
        a, b = b, a
    res = 1
    for k in range(K, -1, -1):
        if D[a][k] < b:
            a = D[a][k]
            res += 2**k
    return res
Q = int(input())
ans = []
for i in range(Q):
    a, b = map(int, input().split())
    ans.append(solve(a-1, b-1))
print(*ans, sep='\n')