Problems
September 1, 2022
Bitwise and of numbers range
If the right crosses the next 2^n of left where n is the number of bits for left, that means 2^n >= left, then the result is always going to be 0. For example, AND product of 1010 and...
September 1, 2022
Minimum height trees
We will first create an adjacency list from the edge list. Then we start BFS from the leaf nodes, and whenever we visit a node, we add this to a list for current leaves, and decreasing the node count...
ReadSeptember 1, 2022
Clumsy factorial
If we calculate some values, then we will notice some pattern. Here are some calculations- From this we can create the following method to calculate the clumsy factorial. Time Complexity:...
ReadAugust 31, 2022
Rearrange words in a sentence
We will split the word with space as delimeter, sort them according to their length, join then again with space, finally return the capitalize string.
Time Complexity: O(nlog(n))...
August 31, 2022
Subarray sum equals k
This problem can't be solved using sliding window as it is not only positive, or only negative or sorted. So, we iterate over each item in the input, calculate prefix sum and store it in a hashmap....
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Continuous subarray sum
We will take a hashmap and keep the reminder along with their index in it. As a base case, we will take the subarray sum as 0 and keep the index -1 as we don't added anything yet in the subarray sum....
ReadAugust 30, 2022
Remove duplicates from sorted list
We will check the current value to the next node value, if they are equal, we remove the current one, and move on till the end of the list.
Time Complexity: O(n)
Space Complexity:...
August 30, 2022
Remove duplicates from sorted list II
We will have 2 pointers, when we iterate over each node, we check if we found duplicate, then we move right pointer until we hit another value. Then remove all nodes between 2 pointers and move both...
ReadAugust 30, 2022
Maximum xor of two numbers in an array
we will create a mask of first character 1 for all 32 position in a 32 bit integer. Then we created hashset to calculate which number has the largest most significant bit. Then we create a temporary...
ReadAugust 30, 2022
Minimum moves to make array complementary
First we create an overlay lookup hashmap of size 2limit+2, as our minimum boundary of change is 2 and maximum is 2limit. Then we iterate over the elements in pair, take the first and last element,...
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