Original Problem


  • The idea here is create a matrix with minimum rows at every round, so we are able to get the maximised value from the number of columns
  • So assume we have n pebbles, the matrix is going to be ab, where a is the number of rows and b is the number of column. And both a and b are positive integers and are divisors of n
  • So the goal now is to find the smallest a aka the smallest divisor of n aka the smallest Prime Number (质数) of the group of prime numbers that composites n
  • The quotient of n is the number of columns aka the number of pebbles we gain and can be used in the next round
  • We repeat this until n is 1 or less

Space & Time Analysis

The analysis method we are using is Algorithm Complexity Analysis

Space - O(1)

  • Ignore input size & language dependent space
  • Not creating any objects on the Heap Segment

Time - O(?)

  • I am not too sure, requires more readings on the time complexity of finding the next prime number
  • But the solution takes 590 ms to complete on codeforces


1st Attempt (Java)

Personal Reflection

  • Why it takes so long to solve: NIL
  • What you could have done better: Be more familiar with Number Theory
  • What you missed: NIL
  • Ideas you’ve seen before: Prime Number (质数)
  • Ideas you found here that could help you later: Abstracting the problem into the a form that I can apply number theory concepts like Prime Number
  • Ideas that didn’t work and why: NIL