## BZOJ1033 | ZJOI2008 杀蚂蚁 AntBuster

<论一次杀蚂蚁的经历>

<论如何优雅地用工程代码风格写出杀蚂蚁>

## BZOJ4241 历史研究

Mo’s Algorithm with Roll-Back

1.对于在同一个块内的询问，$O\left( \sqrt{n} \right)$暴力计算

2.对于不在同一块的询问，莫队排序后，形成了左端点在同一个块内的若干询问，

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## 输入输出格式

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N<=60 M<=240

V<=1000

k<=30

DP求这个部分.

dx怎么求呢？也不好求，所以这就是卡我的地方，我一开始还以为是DFS求

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xjb背包即可.XXXD

## BZOJ3289 Mato的文件管理

Time Limit: 40 Sec (Total)

Memory Limit: 128 MB

## USACO 2007MAR Face The Right Way

 Time Limit: 2000MS Memory Limit: 65536K Total Submissions: 6005 Accepted: 2777

Description

Farmer John has arranged his N (1 ≤ N ≤ 5,000) cows in a row and many of them are facing forward, like good cows. Some of them are facing backward, though, and he needs them all to face forward to make his life perfect.

Fortunately, FJ recently bought an automatic cow turning machine. Since he purchased the discount model, it must be irrevocably preset to turn K (1 ≤ K  N) cows at once, and it can only turn cows that are all standing next to each other in line. Each time the machine is used, it reverses the facing direction of a contiguous group of K cows in the line (one cannot use it on fewer than K cows, e.g., at the either end of the line of cows). Each cow remains in the same *location* as before, but ends up facing the *opposite direction*. A cow that starts out facing forward will be turned backward by the machine and vice-versa.

Because FJ must pick a single, never-changing value of K, please help him determine the minimum value of K that minimizes the number of operations required by the machine to make all the cows face forward. Also determine M, the minimum number of machine operations required to get all the cows facing forward using that value of K.

Input

Line 1: A single integer: N
Lines 2..N+1: Line i+1 contains a single character, F or B, indicating whether cow i is facing forward or backward.

Output

Line 1: Two space-separated integers: K and M

Sample Input

Sample Output

Hint

For K = 3, the machine must be operated three times: turn cows (1,2,3), (3,4,5), and finally (5,6,7)

O(n^2)

## 题目描述

1.注意横坐标上限只与从顶上看的矩阵大小有关，但是纵坐标上限还与高度以及从顶上看的矩阵长度（矩阵纵坐标最大值）有关