摘要：Goldbach's ConjectureIn 1742, Christian Goldbach, a German amateur mathematician, sent a letter to Leonhard Euler in which he made the following conjecture:Every number greater than 2 can be written as the sum of three prime numbers.Goldbach cwas considering 1 as a primer number, a convention th 阅读全文

摘要：THE DRUNK JAILERTime Limit:1000MSMemory Limit:10000KTotal Submissions:21957Accepted:13879DescriptionA certain prison contains a long hall of n cells, each right next to each other. Each cell has a prisoner in it, and each cell is locked.One night, the jailer gets bored and decides to play a game. Fo 阅读全文

摘要：Problem BCode RefactoringTime Limit: 2 seconds"Harry, my dream is a code waiting to bebroken. Break the code, solve the crime."Agent CooperSeveral algorithms in modern cryptography are based on the fact that factoring large numbers is difficult. Alicia and Bobby know this, so they have dec 阅读全文

摘要：Problem F: Factoring Large NumbersOne of the central ideas behind much cryptography is that factoring large numbers is computationally intensive. In this context one might use a 100 digit number that was a product of two 50 digit prime numbers. Even with the fastest projected computers this factoriz 阅读全文

摘要：Light, more lightThe ProblemThere is man named "mabu" for switching on-off light in our University. He switches on-off the lights in a corridor. Every bulb has its own toggle switch. That is, if it is pressed then the bulb turns on. Another press will turn it off. To save power consumption 阅读全文

摘要：Skew BinaryWhen a number is expressed in decimal, thek-th digit represents a multiple of 10k. (Digits are numbered from right to left, where the least significant digit is number 0.) For example,When a number is expressed in binary, thek-th digit represents a multiple of 2k. For example,Inskew binar 阅读全文