feat(interviewcake): add p1 and p2 solutions, p3 in progress

Author: Jessica Yung

interview-cake/p1_to_p5.py

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+import unittest
+
+def get_max_profit(stock_prices_yesterday):
+    """Uses greedy approach. A greedy algorithm iterates through the problem space taking the optimal solution "so far,"
+     until it reaches the end.
+
+    The greedy approach is only optimal if the problem has "optimal substructure," which means stitching together
+    optimal solutions to sub-problems yields an optimal solution.
+    """
+    if len(stock_prices_yesterday) < 2:
+        raise IndexError("Getting a profit requires at least 2 prices.")
+    min_price = stock_prices_yesterday[0]
+    max_profit = stock_prices_yesterday[1] - stock_prices_yesterday[0]
+    for index, price in enumerate(stock_prices_yesterday):
+        if index == 0:
+            continue
+        current_price = price
+        potential_profit = current_price - min_price
+
+        max_profit = max(max_profit, potential_profit)
+
+        min_price = min(min_price, current_price)
+    return max_profit
+
+def get_product_of_all_ints_except_at_index(int_list):
+    # Create list
+    products = [None] * len(int_list)
+    print(products)
+    cum_product = int_list[0]
+    print("First int: ", cum_product)
+    products[0] = 1
+    # Product of all numbers before int
+    for i in range(1, len(int_list)):
+        print("before: ", i, cum_product)
+        products[i] = cum_product
+        cum_product *= int_list[i]
+    # Product of all numbers after int
+    after_product = int_list[-1]
+    for j in range(2,len(int_list)+1):
+        print("after: ", len(int_list)+1-j, after_product)
+        products[-j] *= after_product
+        after_product *= int_list[-j]
+    print(products)
+    return products
+
+
+def my_function(arg):
+    # write the body of your function here
+    return 'running with %s' % arg
+
+
+# run your function through some test cases here
+# remember: debugging is half the battle!
+print
+my_function('test input')
+
+
+def product(list_of_ints):
+    pass
+
+
+def max_three(list_of_ints):
+    pass
+
+
+def min_three(list_of_ints):
+    pass
+
+
+def highest_product_from_list_of_ints(list_of_ints):
+    if len(list_of_ints) == 3:
+        return product(list_of_ints)
+    elif min(list_of_ints) >= 0:
+        return product(max_three(list_of_ints))
+    elif max(list_of_ints) <= 0:
+        return product(min_three(list_of_ints))
+    # If some are positive and some are negative
+    else:
+        sorted_list_of_ints = sorted(list_of_ints)
+
+        max_1 = max(list_of_ints)
+        max_2 = second_max(list_of_ints)
+        min_1 = min(list_of_ints)
+        # min_2 =
+
+
+class Tests(unittest.TestCase):
+    def test_p2_get_product_of_all_ints_except_at_index(self):
+        numbers = [1,2,3]
+        self.assertEqual(get_product_of_all_ints_except_at_index(numbers), [6,3,2])
+
+if __name__ == '__main__':
+    unittest.main()