Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
v_list = []

# print (border)
while t < time :
	v_list = []
	t += 0.5

	#直接制約
	v_list.append(v[idx])
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(n+1):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			v_list.append(temp)
			# if v0 > temp:
			# 	v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			v_list.append(temp)
			# if v0 > temp:
			# 	v0 = temp

	v0 = min(v_list)
#	print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0

# print (border)
while t < time :
	t += 0.5

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(n+1):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			if v0 > temp:
				v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

#	print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0

# print (border)
while t < time :
	t += 0.5

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(n+1):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			if v0 > temp:
				v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

#	print(v0)

	ans += 0.5 * (vlast + v0) / 2
	vlast = v0

print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)

Buggy python submission (verdict: Runtime Error):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0

# print (border)
while t < time :
	t += 0.5
	
	# tle回避
	if t < border[idx+1] and abs(v0- (vlast-0.5) ) < 0.001:
		v0 = vlast - 0.5
		ans += 0.5 * (vlast + v0) / 2
		vlast = v0
		continue

 	vlast = v0

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(n+1):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			if v0 > temp:
				v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

#	print(v0)

	# ans += 0.5 * (vlast + v0) / 2
	ans += 0.5 * (vlast + v0) / 2
# 	vlast = v0

print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0

# print (border)
while t < time :
	t += 0.5
	
	# tle回避
	if t < border[idx+1] and abs(v0- (vlast-0.5) ) < 0.001:
		v0 = vlast - 0.5
		ans += 0.5 * (vlast + v0) / 2
		vlast = v0
		continue

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(len(border)):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			if v0 > temp:
				v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

#	print(v0)

	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0

# print (border)
while t < time :
	t += 0.5
	
	# tle回避
	if t < border[idx+1] and abs(v0- (vlast-0.5) ) < 0.001:
		v0 = vlast - 0.5
		ans += 0.5 * (vlast + v0) / 2
		vlast = v0
		continue

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(len(border)):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			if v0 > temp:
				v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

#	print(v0)
	ans += 0.5 * (vlast + v0) / 2
	vlast = v0

print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)

Buggy python submission (verdict: Time Limit Exceeded):
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);

border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0

# print (border)
while t < time :
	t += 0.5

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
#		v0 = min(v0, v[idx])

	for j in range(len(border)):
		
		if border[j] <= t:
			#前の時刻からの制約
			temp = end_v[j] + (t - border[j])
			if v0 > temp:
				v0 = temp
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

#	print(v0)
	ans += 0.5 * (vlast + v0) / 2
	vlast = v0


print (ans)



Fixed submission:
n = int(input())

tt = list(map(int, input().split()))
v = list(map(int, input().split()))

time = sum(tt);
INF = 999999
border = [0] *(n+1)
start_v = [0] *(n+1)
end_v = [0] *(n+1)

temp = 0
for i in range(n):
	temp += tt[i]
	border[i+1] = temp
	start_v[i] = v[i]
	end_v[i+1] = v[i]

t = 0
idx = 0
ans = 0
vlast = 0
v0 = 0
new_interval = False
limitation_front =0 # 最初の計算に必要

# print (border)
while t < time :
	t += 0.5
	new_interval = False

	#直接制約
	v0 = v[idx]
	if t == border[idx+1]:
		idx += 1
		new_interval = True
#		v0 = min(v0, v[idx])

	if(not new_interval):
		limitation_front += 0.5
		if v0 > limitation_front:
			v0 = limitation_front
	
	if new_interval: 
		limitation_front = INF
		for j in range(n+1):
			if border[j] <= t:
				#前の時刻からの制約
				temp = end_v[j] + (t - border[j])
				if v0 > temp:
					v0 = temp
				if limitation_front > temp:
					limitation_front = temp
			else:
				break
			#print (limitation_front)


	for j in range(n+1):
		if border[j] >= t:
			#後ろの時刻からの制約
			temp = start_v[j] + (border[j] - t)
			if v0 > temp:
				v0 = temp

	#print(v0)

#	ans += 0.5 * (vlast + v0) / 2
	ans += (vlast + v0)
	vlast = v0

ans /= 4.0
print (ans)