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def max_profit_days(stock_prices):
max_profit_amt = 0
max_day_1 = 0
max_day_2 = 1
for day in stock_prices:
i = stock_prices.index(day)
while i < len(stock_prices):
if stock_prices[i] - day > max_profit_amt and i != stock_prices.index(day):
max_day_1 = stock_prices.index(day)
max_day_2 = i
max_profit_amt = stock_prices[i] - day
i+=1
return max_day_1, max_day_2
for j in range(i + 1,len(stock_prices)):
if stock_prices[j] - stock_prices[i] >= high:
high = stock_prices[j] - stock_prices[i]
final = (i,j)
print(final)
else:
continue
I made a helper function to find the index of the maximum (only using the part of the list from a specified index forward),
and I used that in a loop to get the max possible profit for buying on any given day,
and then finding the maximum out of all of those.
my code
def index_of_max(arr, starting_index = 0, ending_index = None):
length = len(arr)
if length < 1:
return None
if ending_index is None:
ending_index = length - 1
else:
length = ending_index + 1
max_so_far = arr[starting_index]
max_index = starting_index
for i in range(starting_index, length):
if arr[i] > max_so_far:
max_so_far = arr[i]
max_index = i
return max_index
def max_profit_days(stock_prices):
length = len(stock_prices)
profits = []
sell_days = []
for i in range(length - 1):
# index i is the day that buy the stock
differences = [(x - stock_prices[i]) for x in stock_prices]
best_day = index_of_max(differences, starting_index = i + 1)
profit = differences[best_day]
profits.append(profit)
sell_days.append(best_day)
#print((i, best_day), profit)
selected_index = index_of_max(profits)
return (selected_index, sell_days[selected_index])
def max_profit_days(days):
highest_profit=None
b_day=None
s_day=None
days=list(days)
length=len(days)
for buy_day in days:
bday_index=days.index(buy_day)+1
for sell_day_index in range(bday_index,length):
sell_day=days[sell_day_index]
profit=sell_day-buy_day
if highest_profit==None or highest_profit<profit:
highest_profit=profit
b_day=days.index(buy_day)
s_day=days.index(sell_day)
return (b_day,s_day)
def max_profit_days(stock_prices):
# Write your code here:
from itertools import permutations
from numpy import Inf
max_ret = -Inf
ret = 0
for open,close in list(permutations(stock_prices,2)):
i_open = stock_prices.index(open)
i_close = stock_prices.index(close)
if i_close > i_open:
if close-open > max_ret:
max_ret = close-open
ret = (i_open,i_close)
return ret
def max_profit_days(stock_prices):
buy_day = 0 #initializing buy day at day 0
sell_day = 1 #initializing buy day at day 1 as it is the first day we can make profit with our stock
stock_roi = (stock_prices[1] - stock_prices[0]) #stock_roi stores the highest roi we can make while iterating over the stock data
for i in range(len(stock_prices)): #iterating over every possible buying day
for j in range(i + 1, len(stock_prices)): #iterating over every possible selling day for a corresponding i
if stock_prices[j] - stock_prices[i] > stock_roi: #if new found roi between days i and j outperformes old stock_roi...
stock_roi = stock_prices[j] - stock_prices[i] #...it becomes the new stock_roi
buy_day = i #for the latest stock_roi which is also the maximum buy_day stores days i...
sell_day = j #...and j
return buy_day, sell_day #so it can return them to the console
print(max_profit_days([17, 11, 60, 25, 150, 75, 31, 120]))
def max_profit_days(stock_prices):
indices = []
for i in range(1,len(stock_prices)):
max_index = stock_prices.index(max(stock_prices[i:]))
min_index = stock_prices.index(min(stock_prices[:max_index]))
if [min_index,max_index] not in indices:
indices.append([min_index,max_index])
differences = [stock_prices[max_index] - stock_prices[min_index] for min_index,max_index in indices]
pairs = dict(zip(differences,indices))
return tuple(pairs.get(max(pairs.keys())))
print(max_profit_days([17, 11, 60, 25, 150, 75, 31, 1]))
If you’re stuck on a test case, remember that losses count too, you HAVE to buy the stock. took me a while to realize why i failed a test case.
def max_profit_days(stock_prices):
maximum = -999999999999999999999999
z =()
for i in range(0, len(stock_prices)):
for j in range(i+1, len(stock_prices)):
a = stock_prices[j] - stock_prices[i]
if a > maximum:
maximum = a
z = (i,j)
if len(z) == 0:
return None
return z
print(max_profit_days([1,9]))
def max_profit_days(stock_prices):
profit = -999999999
result = tuple()
for i in range(len(stock_prices)):
for j in range(i + 1, len(stock_prices)):
current_profit = stock_prices[j] - stock_prices[i]
if current_profit > profit:
profit = current_profit
result = (i,j)
return result
print(max_profit_days([17, 11, 60, 25, 150, 75, 31, 120]))
def max_profit_days(stock_prices):
hold = [0,0,0]
for x in range(0, len(stock_prices)):
for y in range(x, len(stock_prices)):
if stock_prices[y] - stock_prices[x] > hold[2]:
hold[0], hold[1], hold[2] = x, y, stock_prices[y]-stock_prices[x]
if hold[0] == hold[1]: hold[1] += 1
return hold[0], hold[1]
print(max_profit_days([17, 11, 60, 25, 150, 75, 31, 120]))
) below.
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