692. Top K Frequent Words

• Python3 sorting using functools.total_ordering, implements eq and le

98. Validate Binary Search Tree

121. Best Time to Buy and Sell Stock

• get min price before current price

122. Best Time to Buy and Sell Stock II

123. Best Time to Buy and Sell Stock III

188. Best Time to Buy and Sell Stock IV

309. Best Time to Buy and Sell Stock with Cooldown