My Problem Solving Experience

Hi, Folks! Today, I solved three problems on LeetCode: Sum of Subarray Ranges, Largest Rectangle in Histogram, and Evaluate Reverse Polish Notation. All these problems can be solved using a stack, and each problem has a unique logic along with the implementation of stacks.

Sum of Subarray Ranges can be solved both with and without using a stack. Using a brute-force approach, we can solve the problem without a stack. However, using stacks can optimize the solution.

To solve Largest Rectangle in Histogram, we use a stack to store the indices of the bars representing the minimum heights. Using these heights, we calculate the areas and determine the maximum area among them. This approach allows us to solve the problem efficiently.

To solve Evaluate Reverse Polish Notation, we use a stack. We push the digits onto the stack and pop them when we encounter operators, applying the operations accordingly. In this way, we can evaluate the expression.

To solve Sum of Subarray Ranges using stacks, we use two stacks: one to calculate the sum of minimums and the other to calculate the sum of maximums. At the end, we subtract the sum of minimums from the sum of maximums to get the sum of subarray ranges.

I hope my experience will be helpful!

Python3

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