# Problems

June 1, 2023

## Shortest path in binary matrix

We will start BFS from the top left corner of the matrix till we reach the bottom right. Then we will return the shortest path length. Time complexity: `O(n)` Space complexity:...

May 28, 2023

## Number of substrings containing all three characters

We can use a sliding window to solve the problem. We will use a variable `count` to store the number of substrings containing all three characters. Then we will iterate over the string and...

May 28, 2023

## Vowels of all substrings

We can use bottom-up dynamic programming to solve the problem. We will use a variable `vowels` to store the number of vowels in the string. Then we will iterate over the string and update...

May 27, 2023

## Stone game II

We can use top-down dynamic programming to solve the problem. First we will calculate the suffix sum of the piles. Then we will use two pointers `i` and `m` to iterate over the...

May 27, 2023

## Stone game III

We can use top-down dynamic programming to solve the problem. We will use two pointers `i` and `m` to iterate over the piles and the number of stones that can be taken...

May 27, 2023

## Univalued binary tree

We can use depth-first search to solve the problem. We will use a variable `val` to store the value of the root node. Then we will recursively check if the value of the current node is...

May 24, 2023

## Left and right sum differences

We will iterate over the array and compute the sum of the left and right subarrays as we iterate through. Then we will compute the difference between the sums and append it to our result. Finally we...

May 24, 2023

## Count vowel strings in ranges

We construct alambdaboolean functionvowelsto assess whether the word qualifies. Then we map the words using this function. Then we construct the prefix sum of the mapped words. Finally, we return the...

May 23, 2023

## Maximum subsequence score

We can use a heap to store the elements in the array. Then, we can pop the elements from the heap and add them to the result. We will also keep track of the sum of the elements in the heap. If the...