Buggy python submission (verdict: Time Limit Exceeded):
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuel[j][0]:
						fuel[j][0], fuel[j][1] = nc, nm
						nq_append(j)
					elif nc==fuel[j][0] and nm>fuel[j][1]:
						fuel[j][1] = nm
						nq_append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if ans==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)


	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start][0]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
						fuel[j][0], fuel[j][1] = nc, nm
						nq_append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if ans==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)


	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start][0]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[10**10]*N for i in range(N)]
	for s,e,d in P:
		# if d<=L:
		# 	neighbor[s-1].append((e-1,d))
		# 	neighbor[e-1].append((s-1,d))
		if d<=L:
			neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in enumerate(neighbor[i]):	# next node
					if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
						fuel[j][0], fuel[j][1] = nc, nm
						nq_append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if ans==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)


	for s, t in st:
		start, end = s-1, t-1
		if fuellist[start]==0:
			bfs(start,end)
		else:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuel = [100000*(10**10)+L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuel[start] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				# oc, om = fuel[i]
				oc = fuel[i]//(10**10)
				om = fuel[i]%(10**10)
				for j, d in neighbor[i]:	# next node
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					fc = fuel[j]//(10**10)
					fm = fuel[j]%10**10
					# if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
					if nc<fc or (nc==fc and nm>fm):
						# fuel[j][0], fuel[j][1] = nc, nm
						nf = nc*(10**10)+nm
						fuel[j] = nf
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuel[end]//(10**10)
		# if fuel[end][0]==10000000: ans = -1
		if ans==100000: ans = -1

		fuellist[start] = fuel

		print(ans)

	for s, t in st:
		start, end = s-1, t-1
		if fuellist[start]==0:
			bfs(start,end)
		else:
			# ans = fuellist[start][end][0]
			ans = fuellist[start][end]//(10**10)
			if ans==100000: ans = -1
			print(ans)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys

input = sys.stdin.readline

def main():
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:	# next node
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
						fuel[j][0], fuel[j][1] = nc, nm
						nq_append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if fuel[end][0]==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)

	for s, t in st:
		start, end = s-1, t-1
		if fuellist[start]==0:
			bfs(start,end)
		else:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys

input = sys.stdin.readline

def main():
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:	# next node
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
						fuel[j][0], fuel[j][1] = nc, nm
						nq.append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if fuel[end][0]==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)

	for s, t in st:
		start, end = s-1, t-1
		if fuellist[start]==0:
			bfs(start,end)
		else:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Runtime Error):
import sys

input = sys.stdin.readline

def main():
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for pi in P:
		if pi[2]<=L:
			neighbor[pi[0]-1].append((pi[1]-1,pi[2]))
			neighbor[pi[1]-1].append((pi[0]-1,pi[2]))

	fuellist = [0]*N
	n_append = nq.append
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:	# next node
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
						fuel[j][0], fuel[j][1] = nc, nm
						n_append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if fuel[end][0]==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)

	for s, t in st:
		start, end = s-1, t-1
		if fuellist[start]==0:
			bfs(start,end)
		else:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys

input = sys.stdin.readline

def main():
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for pi in P:
		if pi[2]<=L:
			neighbor[pi[0]-1].append((pi[1]-1,pi[2]))
			neighbor[pi[1]-1].append((pi[0]-1,pi[2]))

	start = 0
	end = 2

	fuellist = [0]*N
	def bfs(start, end):
		fuel = [[10000000,L+1] for i in range(N)]
		fuel[start][0] = 0
		fuel[start][1] = L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			for i in queue:				# target node
				oc, om = fuel[i]
				for j, d in neighbor[i]:	# next node
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
						fuel[j][0], fuel[j][1] = nc, nm
						nq.append(j)

			queue = nq					# update target node

		ans = fuel[end][0]
		if fuel[end][0]==10000000: ans = -1

		fuellist[start] = fuel

		print(ans)

	for s, t in st:
		start, end = s-1, t-1
		if fuellist[start]==0:
			bfs(start,end)
		else:
			ans = fuellist[start][end][0]
			if ans==10000000: ans = -1
			print(ans)


if __name__ == '__main__':
	main()

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()

Buggy python submission (verdict: Time Limit Exceeded):
import sys

input = sys.stdin.readline

N, M, L = list(map(int,input().split()))
P = [list(map(int,input().split())) for i in range(M)]
Q = int(input())
st = [list(map(int,input().split())) for i in range(Q)]

neighbor = [[] for i in range(N)]
for pi in P:
	if pi[2]<=L:
		neighbor[pi[0]-1].append((pi[1]-1,pi[2]))
		neighbor[pi[1]-1].append((pi[0]-1,pi[2]))

start = 0
end = 2

def main(start, end):
	fuel = [[10000000,L+1] for i in range(N)]
	fuel[start][0] = 0
	fuel[start][1] = L
	queue = [start]
	while len(queue)>0:
		nq = []						# next target node
		for i in queue:				# target node
			oc, om = fuel[i]
			for j, d in neighbor[i]:	# next node
				if om<d:
					nc = oc+1
					nm = L-d
				else:
					nc = oc
					nm = om-d

				# print(i,j,nc,nm)

				if (nc<fuel[j][0]) or (nc==fuel[j][0] and nm>fuel[j][1]):
					fuel[j][0], fuel[j][1] = nc, nm
					nq.append(j)

		queue = nq					# update target node

	ans = fuel[end][0]
	if fuel[end][0]==10000000: ans = -1

	print(ans)

for s, t in st:
	start, end = s-1, t-1
	main(start,end)

Fixed submission:
import sys


def main():
	input = sys.stdin.readline
	N, M, L = list(map(int,input().split()))
	P = [list(map(int,input().split())) for i in range(M)]
	Q = int(input())
	st = [list(map(int,input().split())) for i in range(Q)]

	neighbor = [[] for i in range(N)]
	for s,e,d in P:
		if d<=L:
			neighbor[s-1].append((e-1,d))
			neighbor[e-1].append((s-1,d))
		# if d<=L:
		# 	neighbor[s-1][e-1] = neighbor[e-1][s-1] = d

	# print(neighbor)
	# start, end = 2,1

	fuellist = [0]*N
	def bfs(start, end):
		# fuel = [[10000000,L+1] for i in range(N)]
		fuelc, fuelm = [10000000]*N, [L+1]*N
		# fuel[start][0] = 0
		# fuel[start][1] = L
		fuelc[start], fuelm[start] = 0, L
		queue = [start]
		while len(queue)>0:
			nq = []						# next target node
			nq_append = nq.append
			for i in queue:				# target node
				oc, om = fuelc[i], fuelm[i]
				for j, d in neighbor[i]:
				# for j, d in enumerate(neighbor[i]):	# next node
					# if d==10**10: continue
					if om<d:
						nc = oc+1
						nm = L-d
					else:
						nc = oc
						nm = om-d

					# print(i,j,nc,nm)

					if nc<fuelc[j]:
						fuelc[j], fuelm[j] = nc, nm
						nq_append(j)
					elif nc==fuelc[j] and nm>fuelm[j]:
						fuelm[j] = nm
						nq_append(j)

			queue = nq					# update target node

		# ans = fuel[end][0]
		ans = fuelc[end]
		if ans==10000000: ans = -1

		fuellist[start] = fuelc

		print(ans)

	for s, t in st:
		start, end = s-1, t-1

		if fuellist[start]!=0:
			ans = fuellist[start][end]
			if ans==10000000: ans = -1
			print(ans)
		elif fuellist[end]!=0:
			ans = fuellist[end][start]
			if ans==10000000: ans = -1
			print(ans)
		else:
			bfs(start,end)


if __name__ == '__main__':
	main()