xinyu04

摘要： A jar begins with one amoeba. Every minute, every amoeba turns into 0, 1, 2, or 3 amoebae with probability 25% for each case ( dies, does nothing, spl 阅读全文

摘要： You have nine pearls, eight are real and one is fake. All the real ones weigh the same and the fake weighs less than the real ones. Using a balance sc 阅读全文

摘要： You are controlling a robot that is located somewhere in a room. The room is modeled as an m x n binary grid where 0 represents a wall and 1 represent 阅读全文

摘要： Using a balance scale and four weights you must be able to balance any integer load from $1$ to $40$. How much should each of the four weights weigh? 阅读全文

摘要： A Range Module is a module that tracks ranges of numbers. Design a data structure to track the ranges represented as half-open intervals and query abo 阅读全文

摘要： Suppose you have a coin in which the probability of flipping a heads is $p$, where $p\ge0.5$ . What is the expected number of flips it will take for t 阅读全文

摘要： Show that any prime number other than 2 can be expressed as the difference of two squares, where each square is an integer squared. Solution 任何质数都是奇数。 阅读全文

摘要： How many subsquares can you form on chessboard with $n*n$ unit squares? Subsquares must be an integer squared. Solution 很明显的方法就是枚举正方形的边长，然后统计该边长的正方形的个 阅读全文

摘要： Given a list of 24-hour clock time points in "HH:MM" format, return the minimum minutes difference between any two time-points in the list. Solution 这 阅读全文

摘要： You are given an m x n binary matrix grid. In one operation, you can choose any row or column and flip each value in that row or column (i.e., changin 阅读全文