eli.thegreenplace.net

The Chinese Remainder Theorem

The Chinese Remainder Theorem (CRT) is very useful in cryptography and other domains. According to Wikipedia, its origin and name come from this riddle in a 3rd century book by a Chinese mathematician: There are certain things whose number is unknown. If we count them by threes, we have two left over; by fives, we have three left over; and by sevens, two are left over. How many things are there? Mathematically, this is a system of linear congruences. In this post we'll go through a simple proof of the existence of a solution. It also...

programmer group

Leetcode 453. Minimum Moves to Equal Array Elements

Topic Requirements Given a non-empty integer array of size n, find the minimum number of moves required to make all array elements equal, where a move is incrementing n - 1 elements by 1. Example: Input: [1,2,3] Output: 3 Explanation: Only three moves are needed (remember each move increments two elements): [1,2,3] => [2,3,3] => [3,4,3] => [4,4,4] From a non-empty integer array of length n, find the minimum number of steps that can make the values of each element in the array equal. One step is to select an n-1 element...