Will IOI '16 live contest standing be available? If yes , please get me the link . Thanks

Problem Link: https://www.codechef.com/LTIME36/problems/ASTRING This problem can be solved using a segment tree RMQ. But I'm thinking of an alternative greedy approach which isn't working. I'm getting constant WA.

The idea is : since we need to take a substring of length k we need to perform (n — k) remove operations. So I'm removing the largest character in the string starting from the minimum index and this is supposed to ensure the lexicographically smallest substring. This approach gets WA. Anyone with bug in my approach or any counter example will be appreciated. Thanks.

Segment tree code : http://pastebin.com/gkx44cTP

My greedy code : http://pastebin.com/gEV1chkC

What is the most efficient way to find the center and radius of a weighted tree?

Someone please help me with this problem : http://poj.org/problem?id=1944 I cannot figure out the DP.