[50, 100, 120, 130, 250]
Buy stock on day 1 (50)
, Sell stock on day 5 (250)
[140, 20, 150, 10, 350]
Buy stock on day 2 (20)
, Sell stock on day 3 (150)
, etc.[50, 100, 120, 130, 250]
→ Output: Buy stock on day 1 (50)
, Sell stock on day 5 (250)
[140, 20, 150, 10, 350]
→ Output: Buy stock on day 2 (20)
, Sell stock on day 3 (150)
, etc.O(n^2)
.