Satellite Photographs

最新推荐文章于 2020-02-27 11:15:28 发布

Flaygo

最新推荐文章于 2020-02-27 11:15:28 发布

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CC 4.0 BY-SA版权

本文链接：https://blog.youkuaiyun.com/daoqin121/article/details/39321657

本文介绍了一种用于计算卫星照片中最大连续牧场面积的算法。该算法通过遍历二维数组并使用深度优先搜索来标记和计算牧场面积，最终找出最大的牧场区域。

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Description

Farmer John purchased satellite photos of W x H pixels of his farm (1 <= W <= 80, 1 <= H <= 1000) and wishes to determine the largest 'contiguous' (connected) pasture. Pastures are contiguous when any pair of pixels in a pasture can be connected by traversing adjacent vertical or horizontal pixels that are part of the pasture. (It is easy to create pastures with very strange shapes, even circles that surround other circles.)
Each photo has been digitally enhanced to show pasture area as an asterisk ('*') and non-pasture area as a period ('.'). Here is a 10 x 5 sample satellite photo:
..*.....** .**..***** .*...*.... ..****.*** ..****.***
This photo shows three contiguous pastures of 4, 16, and 6 pixels. Help FJ find the largest contiguous pasture in each of his satellite photos.

Input

* Line 1: Two space-separated integers: W and H
* Lines 2..H+1: Each line contains W "*" or "." characters representing one raster line of a satellite photograph.

Output

* Line 1: The size of the largest contiguous field in the satellite photo.

Sample Input

10 5
..*.....**
.**..*****
.*...*....
..****.***
..****.***

Sample Output

#include<iostream>
using namespace std;
char a[1500][1500];
int num;
void f(int x,int y)
{

if(a[x][y]=='*')
{
     a[x][y]='.';
     num++;
   f(x,y+1);
   f(x,y-1);
   f(x+1,y);
   f(x-1,y);
}
}
int main()
{
   int m,n,i,j,max=0;
   cin>>m>>n;
   for(i=1;i<=n;i++)
       for(j=1;j<=m;j++)
           cin>>a[i][j];

     for(i=1;i<=n;i++)
         {
             for(j=1;j<=m;j++)
           {
                 num=0;
                 f(i,j);
                  if(num>max)
                      max=num;
             }
        }

cout<<max<<endl;

}