1691. Maximum Height by Stacking Cuboids
Given n cuboids where the dimensions of the ith cuboid is cuboids[i] = [widthi, lengthi, heighti] (0-indexed). Choose a subset of cuboids and place them on each other.
You can place cuboid i on cuboid j if widthi <= widthj and lengthi <= lengthj and heighti <= heightj. You can rearrange any cuboid’s dimensions by rotating it to put it on another cuboid.
Return the maximum height of the stacked cuboids.
1610. Maximum Number of Visible Points
You are given an array points, an integer angle, and your location, where location = [posx, posy] and points[i] = [xi, yi] both denote integral coordinates on the X-Y plane.
Initially, you are facing directly east from your position. You cannot move from your position, but you can rotate. In other words, posx and posy cannot be changed. Your field of view in degrees is represented by angle, determining how wide you can see from any given view direction. Let d be the amount in degrees that you rotate counterclockwise. Then, your field of view is the inclusive range of angles [d - angle/2, d + angle/2].
You can see some set of points if, for each point, the angle formed by the point, your position, and the immediate east direction from your position is in your field of view.
There can be multiple points at one coordinate. There may be points at your location, and you can always see these points regardless of your rotation. Points do not obstruct your vision to other points.
Return the maximum number of points you can see.
1240. Tiling a Rectangle with the Fewest Squares
Given a rectangle of size n x m, return the minimum number of integer-sided squares that tile the rectangle.
Your car starts at position 0 and speed +1 on an infinite number line. Your car can go into negative positions. Your car drives automatically according to a sequence of instructions ‘A’ (accelerate) and ‘R’ (reverse):
When you get an instruction ‘A’, your car does the following:
- position += speed
- speed *= 2
When you get an instruction ‘R’, your car does the following:
- If your speed is positive then speed = -1
- otherwise speed = 1
Your position stays the same.
For example, after commands “AAR”, your car goes to positions 0 —> 1 —> 3 —> 3, and your speed goes to 1 —> 2 —> 4 —> -1.Given a target position target, return the length of the shortest sequence of instructions to get there.
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.