This notebook was prepared by Donne Martin. Source and license info is on GitHub.

- Are all prices positive ints?
- Yes

- Is the output an int?
- Yes

- If profit is negative, do we return the smallest negative loss?
- Yes

- If there are less than two prices, what do we return?
- Exception

- Can we assume the inputs are valid?
- No

- Can we assume this fits memory?
- Yes

- None -> TypeError
- Zero or one price -> ValueError
- No profit
- [8, 5, 3, 2, 1] -> -1

- General case
- [5, 3, 7, 4, 2, 6, 9] -> 7

Refer to the Solution Notebook. If you are stuck and need a hint, the solution notebook's algorithm discussion might be a good place to start.

In [ ]:

```
class Solution(object):
def find_max_profit(self, prices):
# TODO: Implement me
pass
```

**The following unit test is expected to fail until you solve the challenge.**

In [ ]:

```
# %load test_max_profit.py
import unittest
class TestMaxProfit(unittest.TestCase):
def test_max_profit(self):
solution = Solution()
self.assertRaises(TypeError, solution.find_max_profit, None)
self.assertRaises(ValueError, solution.find_max_profit, [])
self.assertEqual(solution.find_max_profit([8, 5, 3, 2, 1]), -1)
self.assertEqual(solution.find_max_profit([5, 3, 7, 4, 2, 6, 9]), 7)
print('Success: test_max_profit')
def main():
test = TestMaxProfit()
test.test_max_profit()
if __name__ == '__main__':
main()
```

Review the Solution Notebook for a discussion on algorithms and code solutions.