Given a m x n matrix mat and an integer k, return a matrix answer where each answer[i][j] is the sum of all elements mat[r][c] for:
- i - k <= r <= i + k,
- j - k <= c <= j + k, and
- (r, c) is a valid position in the matrix.
Given a m x n matrix mat and an integer k, return a matrix answer where each answer[i][j] is the sum of all elements mat[r][c] for:
- i - k <= r <= i + k,
- j - k <= c <= j + k, and
- (r, c) is a valid position in the matrix.
304. Range Sum Query 2D - Immutable
Given a 2D matrix matrix, handle multiple queries of the following type:
- Calculate the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2).
Implement the NumMatrix class:
- NumMatrix(int[][] matrix) Initializes the object with the integer matrix matrix.
- int sumRegion(int row1, int col1, int row2, int col2) Returns the sum of the elements of matrix inside the rectangle defined by its upper left corner (row1, col1) and lower right corner (row2, col2).
Given two strings ransomNote and magazine, return true if ransomNote can be constructed from magazine and false otherwise.
Each letter in magazine can only be used once in ransomNote.
387. First Unique Character in a String
Given a string s, find the first non-repeating character in it and return its index. If it does not exist, return -1.
104. Maximum Depth of Binary Tree
Given the root of a binary tree, return its maximum depth.
A binary tree’s maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node.
We are given a list schedule of employees, which represents the working time for each employee.
Each employee has a list of non-overlapping Intervals, and these intervals are in sorted order.
Return the list of finite intervals representing common, positive-length free time for all employees, also in sorted order.
(Even though we are representing Intervals in the form [x, y], the objects inside are Intervals, not lists or arrays. For example, schedule[0][0].start = 1, schedule[0][0].end = 2, and schedule[0][0][0] is not defined). Also, we wouldn’t include intervals like [5, 5] in our answer, as they have zero length.
2172. Maximum AND Sum of Array
You are given an integer array nums of length n and an integer numSlots such that 2 * numSlots >= n. There are numSlots slots numbered from 1 to numSlots.
You have to place all n integers into the slots such that each slot contains at most two numbers. The AND sum of a given placement is the sum of the bitwise AND of every number with its respective slot number.
- For example, the AND sum of placing the numbers [1, 3] into slot 1 and [4, 6] into slot 2 is equal to (1 AND 1) + (3 AND 1) + (4 AND 2) + (6 AND 2) = 1 + 1 + 0 + 2 = 4.
Return the maximum possible AND sum of nums given numSlots slots.
2171. Removing Minimum Number of Magic Beans
You are given an array of positive integers beans, where each integer represents the number of magic beans found in a particular magic bag.
Remove any number of beans (possibly none) from each bag such that the number of beans in each remaining non-empty bag (still containing at least one bean) is equal. Once a bean has been removed from a bag, you are not allowed to return it to any of the bags.
Return the minimum number of magic beans that you have to remove.
2170. Minimum Operations to Make the Array Alternating
You are given a 0-indexed array nums consisting of n positive integers.
The array nums is called alternating if:
- nums[i - 2] == nums[i], where 2 <= i <= n - 1.
- nums[i - 1] != nums[i], where 1 <= i <= n - 1.
In one operation, you can choose an index i and change nums[i] into any positive integer.
Return the minimum number of operations required to make the array alternating.
2169. Count Operations to Obtain Zero
You are given two non-negative integers num1 and num2.
In one operation, if num1 >= num2, you must subtract num2 from num1, otherwise subtract num1 from num2.
- For example, if num1 = 5 and num2 = 4, subtract num2 from num1, thus obtaining num1 = 1 and num2 = 4. However, if num1 = 4 and num2 = 5, after one operation, num1 = 4 and num2 = 1.
Return the number of operations required to make either num1 = 0 or num2 = 0.