# SuperUserDo

## Problem Statement

Fox Ciel just used the command "sudo" (super-user do) to gain administrative privileges in the UNIX-based operating system on her computer. She now wants to install several new programs. Each program has some dependencies: in addition to the program, the package manager has to install some libraries used by the program.
The package repository contains exactly 1000 libraries. For simplicity, we will number them from 1 to 1000, inclusive.
You are given the information about the dependencies of the programs Fox Ciel wants to install. More precisely, you are given the int[]s A and B, both containing the same number of elements. For each valid i, one of the programs needs all libraries that have numbers between A[i] and B[i], inclusive. Note that the programs may have overlapping dependences: multiple programs may require the same library to be installed. Of course, in such cases it is sufficient to install such a library once.
Calculate and return the total number of libraries that need to be installed.

# Codeforces Round#371 Div.2

## A. Meeting of Old Friends

Today an outstanding event is going to happen in the forest — hedgehog Filya will come to his old fried Sonya!

Sonya is an owl and she sleeps during the day and stay awake from minute l1 to minute r1 inclusive. Also, during the minute k she prinks and is unavailable for Filya.

Filya works a lot and he plans to visit Sonya from minute l2 to minute r2 inclusive.

Calculate the number of minutes they will be able to spend together.

# Codeforces Round#369 Div.2

## A. Bus to Udayland

ZS the Coder and Chris the Baboon are travelling to Udayland! To get there, they have to get on the special IOI bus. The IOI bus has nrows of seats. There are 4 seats in each row, and the seats are separated into pairs by a walkway. When ZS and Chris came, some places in the bus was already occupied.

ZS and Chris are good friends. They insist to get a pair of neighbouring empty seats. Two seats are considered neighbouring if they are in the same row and in the same pair. Given the configuration of the bus, can you help ZS and Chris determine where they should sit?

# [bzoj 1057][ZJOI2007] 棋盘制作

## Description

国际象棋是世界上最古老的博弈游戏之一，和中国的围棋、象棋以及日本的将棋同享盛名。据说国际象棋起源于易经的思想，棋盘是一个8*8大小的黑白相间的方阵，对应八八六十四卦，黑白对应阴阳。而我们的主人公小Q，正是国际象棋的狂热爱好者。作为一个顶尖高手，他已不满足于普通的棋盘与规则，于是他跟他的好朋友小W决定将棋盘扩大以适应他们的新规则。小Q找到了一张由N*M个正方形的格子组成的矩形纸片，每个格子被涂有黑白两种颜色之一。小Q想在这种纸中裁减一部分作为新棋盘，当然，他希望这个棋盘尽可能的大。不过小Q还没有决定是找一个正方形的棋盘还是一个矩形的棋盘（当然，不管哪种，棋盘必须都黑白相间，即相邻的格子不同色），所以他希望可以找到最大的正方形棋盘面积和最大的矩形棋盘面积，从而决定哪个更好一些。于是小Q找到了即将参加全国信息学竞赛的你，你能帮助他么？

# [bzoj 1084][SCOI2005] 最大子矩阵

## Description

这里有一个n*m的矩阵，请你选出其中k个子矩阵，使得这个k个子矩阵分值之和最大。注意：选出的k个子矩阵不能相互重叠。