HDU-1241 Oil Deposits

最新推荐文章于 2019-07-19 09:07:49 发布

深海幽藍

最新推荐文章于 2019-07-19 09:07:49 发布

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分类专栏： dfs

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本文介绍了一个用于探测和计数矩形区域内相连油田数量的算法。该算法通过深度优先搜索（DFS）来识别并标记相连的油井，从而确定不同油田的数量。输入包含一系列矩形网格地图，每个格子用字符表示是否有油井，输出则是独立油田的总数。

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The GeoSurvComp geologic survey company is responsible for detecting underground oil deposits. GeoSurvComp works with one large rectangular region of land at a time, and creates a grid that divides the land into numerous square plots. It then analyzes each plot separately, using sensing equipment to determine whether or not the plot contains oil. A plot containing oil is called a pocket. If two pockets are adjacent, then they are part of the same oil deposit. Oil deposits can be quite large and may contain numerous pockets. Your job is to determine how many different oil deposits are contained in a grid.

Input

The input contains one or more grids. Each grid begins with a line containing m and n, the number of rows and columns in the grid, separated by a single space. If m = 0 it signals the end of the input; otherwise 1 <= m <= 100 and 1 <= n <= 100. Following this are m lines of n characters each (not counting the end-of-line characters). Each character corresponds to one plot, and is either `*', representing the absence of oil, or `@', representing an oil pocket.

Output

are adjacent horizontally, vertically, or diagonally. An oil deposit will not contain more than 100 pockets.

Sample Input

1 1
*
3 5
*@*@*
**@**
*@*@*
1 8
@@****@*
5 5 
****@
*@@*@
*@**@
@@@*@
@@**@
0 0

Sample Output

0
1
2

题意：判断相连（八个方向）的油田数

#include<iostream>
#include<cstdlib>
#include<cstring>
using namespace std;
int n,m;
int answer;
char a[105][105];
bool judge(int x,int y)
{
    if(x>=1&&y>=1&&x<=n&&y<=m)
        return 1;
    else
        return 0;
}
void dfs(int x,int y)
{
    if(judge(x,y)&&a[x][y]=='@')
    {
    a[x][y]='*';
    dfs(x-1,y-1);dfs(x-1,y);dfs(x-1,y+1);
    dfs(x,y-1);             dfs(x,y+1);
    dfs(x+1,y-1);dfs(x+1,y);dfs(x+1,y+1);
    }
    else
        return;
}
int main()
{
    while(cin>>n>>m)
    {
        if(m==0&&n==0)
            return 0;
        answer=0;
        memset(a,0,sizeof(a));
        for(int i=0;i<=103;i++)          //将边界初始化为*  不知道为什么 去掉就运行不出来！！
        {
            for(int j=0;j<=103;j++)
            {
                a[i][j]='*';
            }
        }
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=m;j++)
            {
                cin>>a[i][j];
            }
        }
        for(int i=1;i<=n;i++)
        {
            for(int j=1;j<=m;j++)
            {
                if(a[i][j]=='@'&&judge(i,j))
                {
                    answer++;
                    dfs(i,j);
                }
                else
                    continue;
            }
        }
        cout<<answer<<endl;
    }
    return 0;
}