Given the coordinates of four points in 2D space p1, p2, p3 and p4, return true if the four points construct a square.
The coordinate of a point pi is represented as [xi, yi]. The input is not given in any order.
A valid square has four equal sides with positive length and four equal angles (90-degree angles).
562. Longest Line of Consecutive One in Matrix
Given an m x n binary matrix mat, return the length of the longest line of consecutive one in the matrix.
The line could be horizontal, vertical, diagonal, or anti-diagonal.
Design a logger system that receives a stream of messages along with their timestamps. Each unique message should only be printed at most every 10 seconds (i.e. a message printed at timestamp t will prevent other identical messages from being printed until timestamp t + 10).
All messages will come in chronological order. Several messages may arrive at the same timestamp.
Implement the Logger class:
- Logger() Initializes the logger object.
- bool shouldPrintMessage(int timestamp, string message) Returns true if the message should be printed in the given timestamp, otherwise returns false.
727. Minimum Window Subsequence
Given strings s1 and s2, return the minimum contiguous substring part of s1, so that s2 is a subsequence of the part.
If there is no such window in s1 that covers all characters in s2, return the empty string “”. If there are multiple such minimum-length windows, return the one with the left-most starting index.
552. Student Attendance Record II
An attendance record for a student can be represented as a string where each character signifies whether the student was absent, late, or present on that day. The record only contains the following three characters:
- ‘A’: Absent.
- ‘L’: Late.
- ‘P’: Present.
Any student is eligible for an attendance award if they meet both of the following criteria:
- The student was absent (‘A’) for strictly fewer than 2 days total.
- The student was never late (‘L’) for 3 or more consecutive days.
Given an integer n, return the number of possible attendance records of length n that make a student eligible for an attendance award. The answer may be very large, so return it modulo 109 + 7.
Implement a basic calculator to evaluate a simple expression string.
The expression string contains only non-negative integers, ‘+’, ‘-‘, ‘*’, ‘/‘ operators, and open ‘(‘ and closing parentheses ‘)’. The integer division should truncate toward zero.
You may assume that the given expression is always valid. All intermediate results will be in the range of [-231, 231 - 1].
Note: You are not allowed to use any built-in function which evaluates strings as mathematical expressions, such as eval().
2092. Find All People With Secret
You are given an integer n indicating there are n people numbered from 0 to n - 1. You are also given a 0-indexed 2D integer array meetings where meetings[i] = [xi, yi, timei] indicates that person xi and person yi have a meeting at timei. A person may attend multiple meetings at the same time. Finally, you are given an integer firstPerson.
Person 0 has a secret and initially shares the secret with a person firstPerson at time 0. This secret is then shared every time a meeting takes place with a person that has the secret. More formally, for every meeting, if a person xi has the secret at timei, then they will share the secret with person yi, and vice versa.
The secrets are shared instantaneously. That is, a person may receive the secret and share it with people in other meetings within the same time frame.
Return a list of all the people that have the secret after all the meetings have taken place. You may return the answer in any order.
Given an integer rowIndex, return the rowIndexth (0-indexed) row of the Pascal’s triangle.
In Pascal’s triangle, each number is the sum of the two numbers directly above it as shown:
Given an integer numRows, return the first numRows of Pascal’s triangle.
In Pascal’s triangle, each number is the sum of the two numbers directly above it as shown:
In MATLAB, there is a handy function called reshape which can reshape an m x n matrix into a new one with a different size r x c keeping its original data.
You are given an m x n matrix mat and two integers r and c representing the number of rows and the number of columns of the wanted reshaped matrix.
The reshaped matrix should be filled with all the elements of the original matrix in the same row-traversing order as they were.
If the reshape operation with given parameters is possible and legal, output the new reshaped matrix; Otherwise, output the original matrix.
