Problems
July 23, 2022
Task scheduler
We will first count each characters and create a max heap out of it. Then we pop the item from the heap, put it on a queue, and increase the value of our counter. Then we process the task, if there...
ReadJuly 23, 2022
Plus one
First we reverse the list, then add one to the fist item, if the number is 9, then we keep a carry and add it to the next number. We will do that until all the digit in the list have been iterated...
ReadJuly 23, 2022
K closest points to origin
First we will calculate all the distances from the origin and put that on a list. Then we heapify that list, then pop top k elements and put their coordinate on a result array and return that....
ReadJuly 23, 2022
Subsets
We will do backtracking to solve the result. For each element of the list, we have 2 option, either we take the element or we leave the element. From this base case, if we run dfs for from the...
ReadJuly 23, 2022
Design add and search words data structure
We will implement the trie as normal, the addWord function will be identical to a normal trie. The search function will be a little different. We will iterate over each character, if the character is...
ReadJuly 23, 2022
Kth largest element in an array
We can just sort the element and return second largest element from the array, but it will have O(nlog(n)) time complexity. But if we use a heap, then the time complexity will be...
July 23, 2022
Remove nth node from end of list
We will have 2 pointer, first we move the right pointer to nth node. Then we move both left and right pointer until the right pointer moves to the end of the list, that means left pointer is now on...
ReadJuly 22, 2022
Jump game II
This is very similar to jump game, we will go for a greedy approah. We will have 2 pointer, left and right to determine the level of each move. In every iteration we will calculate the maximum number...
ReadJuly 22, 2022
N-queens
We will have 3 different sets, one for the column, one for positive diagonal and one for negative diagonal. We will iterate over the each row, and try to add the queen in the board. If this is...
Read