I got selection to IOITC this year. I would like to know more about the camp and topics which will be discussed there. Will they teach the whole syllabus of IOI in the camp within a span 10 days? What all should I learn before attending the camp in order to understand everything discussed there in a more better way?

This seems to be quite an interesting problem from IOITC 2013.

Problem in Short: You are given N distinct points on a plane where distances are measured using the Manhattan metric. Find the number of ordered triplets of distinct points (A;B;C) such that the sum of distances from A to B and B to C is equal to the distance from A to C.

I have been trying this problem for quite some time but unable to come up with a solution to pass the following constraints: N<=10^5 and |xi|<=10^9 , |yi|<=10^9.

Some hints to get me unstuck would be highly appreciated. Thank you.

Problem In Short:

Given two nodes s and t in a weighted graph and Q queries to handle.

For every query you are given an edge to remove from the graph and you have to compute the shortest path between s and t.

Queries are independent, that is after you handle one query, reinsert the edge for subsequent queries.

N <= 7000, M <= 50000, Q <= 10000

(Please provide some hints, I'm unable to think a better solution than O(NM log N))

Hi,

I've been doing some past IOITC problems for a while now, but due to lack of time before TC I started only from 2014 onwards. I was wondering if there are some more interesting, non-trivial problems from before 2014 besides the one I tried, Facebook, 2012. Would be great help if you named a few!

Thanks!

This seems like a very good problem unfortunately my mind has been unable to make much progress. Therefore hints would be very appreciated :D. Here is the problem:

Today, we have a very interesting problem for you. Given an array A of N integers indexed from 1 to N, you need to perform following two types of queries :

• Change the value of A[x] to k.

• Find the kth ranked element in the subarray A[x..y] (x and y inclusive). An element is said to have kth rank if its position is k when the subarray is sorted in ascending order.

Can you perform these queries efficiently?