All Questions
6
questions with no upvoted or accepted answers
2
votes
0
answers
34
views
Astronomer watching planets in a solar system
There is exactly one astronomer on every planet of a certain system. He watches the closest planet. The number of the planets is odd and all of the distances are different. Prove that there one planet ...
- 162
2
votes
0
answers
166
views
Greedy algorithm minimizes the sum
There are $n$ positive numbers (not necessarily distinct). In every step, we
can select two numbers and replace each of it with the sum of the two
numbers. Prove that in any amount of steps, selecting ...
- 1,909
1
vote
0
answers
48
views
Squared multiplicty minimization in multiple set choosing problem
The problem is the IOI 2007 competition's Sails problem. It has also appeared in Pranav A. Sriram Olympiad Combinatorics notes (Chapter 1 Exercise 14). I copied the problem description from Pranav. ...
- 11
1
vote
0
answers
95
views
Building a primitive programming language for solving math olympiad problem(TSTST 2015)
There was a 6th problem on USA TSTST 2015:
A Nim-style game is defined as follows. Two positive integers $k$ and
$n$ are specified, along with a finite set $S$ of $k$-tuples of
integers (not ...
- 61
1
vote
1
answer
342
views
Count ways to distribute candies
N students sit in a line, and each of them must be given at least one candy. Teacher wants to distribute the candies in such a way that the product of the number of candies any two adjacent students ...
- 272
0
votes
1
answer
56
views
Number of ways of traversing a graph through all of its nodes?
A lift has $N$ stops ($1,2,3,4,...,N$), hence have $N(N-1)$ distinct rides of travelling from floor $A$ to floor $B$ such that $A\neq B$. How many arrangements of these rides form a continuous trip ...
- 51