ZOJ 1002:Fire Net
来源:互联网 发布:大数据英文怎么说 编辑:程序博客网 时间:2024/05/21 18:35
Suppose that we have a square city with straight streets. A map of a city is a square board with n rows and n columns, each representing a street or a piece of wall.
A blockhouse is a small castle that has four openings through which to shoot. The four openings are facing North, East, South, and West, respectively. There will be one machine gun shooting through each opening.
Here we assume that a bullet is so powerful that it can run across any distance and destroy a blockhouse on its way. On the other hand, a wall is so strongly built that can stop the bullets.
The goal is to place as many blockhouses in a city as possible so that no two can destroy each other. A configuration of blockhouses is legal provided that no two blockhouses are on the same horizontal row or vertical column in a map unless there is at least one wall separating them. In this problem we will consider small square cities (at most 4x4) that contain walls through which bullets cannot run through.
The following image shows five pictures of the same board. The first picture is the empty board, the second and third pictures show legal configurations, and the fourth and fifth pictures show illegal configurations. For this board, the maximum number of blockhouses in a legal configuration is 5; the second picture shows one way to do it, but there are several other ways.
Your task is to write a program that, given a description of a map, calculates the maximum number of blockhouses that can be placed in the city in a legal configuration.
The input file contains one or more map descriptions, followed by a line containing the number 0 that signals the end of the file. Each map description begins with a line containing a positive integer n that is the size of the city; n will be at most 4. The next n lines each describe one row of the map, with a '.' indicating an open space and an uppercase 'X' indicating a wall. There are no spaces in the input file.
For each test case, output one line containing the maximum number of blockhouses that can be placed in the city in a legal configuration.
Sample input:
4.X......XX......2XX.X3.X.X.X.X.3....XX.XX4................0
Sample output:
51524
Source: Zhejiang University Local Contest 2001
迷失在幽谷中的鸟儿,独自飞翔在这偌大的天地间,却不知自己该飞往何方……
#include<iostream>#include<stdio.h>#include<string.h>using namespace std;char map[5][5];int k[5][5];int n,ab;bool ok(int a,int b){ for(int i=b-1; i>=0&&map[a][i]!='X'; i--) if(k[a][i])return false; for(int i=a-1; i>=0&&map[i][b]!='X'; i--) if(k[i][b])return false; return true;}void huisu(int a,int b,int m){ for(int i=a; i<n; i++) { if(i>a)b=-1; for(int j=b+1; j<n; j++) { if(map[i][j]=='X')continue; if(ok(i,j)) { k[i][j]=1; huisu(i,j,m+1); k[i][j]=0; } } } ab=ab<m?m:ab;}int main(){ while(cin>>n&&n) { ab=0; memset(map,0,sizeof(map)); memset(k,0,sizeof(k)); getchar(); for(int i=0; i<n; i++) gets(map[i]); for(int i=0; i<n; i++) for(int j=0; j<n; j++) { if(map[i][j]=='X')continue; k[i][j]=1; huisu(i,j,1); k[i][j]=0; } cout<<ab<<endl; } return 0;}
- ZOJ-1002-Fire Net
- ZOJ 1002 Fire Net
- ZOJ 1002 Fire Net
- ZOJ 1002 Fire Net
- zoj 1002 Fire Net
- zoj 1002 Fire Net
- ZOJ 1002 Fire Net
- ZOJ 1002 Fire Net
- ZOJ 1002 Fire Net
- ZOJ 1002 Fire Net
- zoj 1002 Fire Net
- ZOJ 1002 Fire Net
- zoj 1002 Fire Net
- zoj 1002 Fire Net
- zoj 1002 Fire Net
- ZOJ-1002 Fire Net
- ZOJ 1002 Fire Net
- ZOJ 1002 Fire Net
- 【Android开发小记--7】动画--简单的button移动和图片3D翻转
- 哈理工OJ 1692【水题】
- 基于IBM Bluemix的数据缓存应用实例
- 轻蔑这个,鄙视那个,眼高手低,好高骛远,有点料就忍不住到处兜售
- NSURLSession实现图片下载
- ZOJ 1002:Fire Net
- 查找算法之折半查找
- poj 3252 Round Numbers 【数位dp】
- C#成神之路<9> C#引用数据类型扩展
- 模板方式
- java中快速创建带初始值的List和Map
- Codeforces 351D:Jeff and Removing Periods
- [POJ 3349]Snowflake Snow Snowflakes[hash]
- 【树链剖分】[BZOJ1036][ZJOI2008]树的统计Count