The idea is pretty simple, we use a map to record the number appearance for each letter from the ransomNote. Then we go to magazine and see if each letter can be used in the ransomNote. Each time we see… Read More »Leetcode 383 Ransom Note
The most intuitive solution would be to go over each cell of the board, base on its neighbors, record the new value in a temporary board. Then after all cells are done, we loop through the original board again and… Read More »Leetcode 289 Game of Life
There are straight forward solutions for this problem but they are require extra space. The best solution only ask for O(1) of space. The reason why we need extra space in the first place is because we need to store… Read More »Leetcode 73 Set Matrix Zeroes
This is an interesting problem which looks complex but essentially there are just 2 steps we need to do this. Solution Javascript: Time Complexity:O(n^2) since we visited all the cells in the matrix Space Complexity:O(1) since it’s in place
This is indeed a very interesting problem. If we simulate the process, there are a couple of key points to notice: Solution Javascript: Time Complexity:O(m*n) since we visited all the cells in the matrix Space Complexity:O(1)
Problem Statement Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: Note: Examples Constraints Solution Python: Java:
Problem Statement Given an array of integers nums and an integer target, return the indices of the two numbers such that they add up to target. You may assume that each input would have exactly one solution, and you may not use the same… Read More »Leetcode 1 Two Sum