layout: post
title: 2018-2019 ACM-ICPC Southeastern European Regional Programming Contest (SEERC 2018)
author: "luowentaoaa"
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- codeforces
C. Tree (violence)
The meaning of problems
Give you a tree, the tree has black and white spots and let you choose m black dots makes them the longest distance is the shortest. Output longest distance.
Thinking
Direct enumeration of two black spots, the other to the maximum points from two black dots can not exceed the distance between them.
E - Fishermen (difference)
The meaning of problems
Do not speak sign.
K - Points and Rectangles (cdq 分治)
The meaning of problems
Each time you add a matrix and point, every time you add need to check all the points of the matrix number
Thinking
Find the midpoint of the number of matrix template, find how many points in the matrix, can be the difference, how many lower-left corner of the matrix in the lower-left point of demand.