P-Oil Deposits

最新推荐文章于 2019-07-24 13:56:00 发布

原创最新推荐文章于 2019-07-24 13:56:00 发布 · 487 阅读

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本文介绍了一个用于探测地下石油储藏的算法。通过分析一个大型矩形土地区域，并将其划分为多个正方形地块进行单独分析，确定是否存在石油。相邻的石油地块被视为同一储藏区的一部分。文章提供了使用深度优先搜索（DFS）算法来确定不同石油储藏区数量的C++实现。

Description
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 file 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
For each grid, output the number of distinct oil deposits. Two different pockets are part of the same oil deposit if they 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
2

找石油，向八个方向搜索，搜索完一处，将该处变成石头。

#include <stdio.h>
#include<algorithm>
#include<iostream>
using namespace std;
char map[101][101];
int n, m, p;
void dfs(int i, int j)
{
    if(map[i][j]!='@' || i<0 || j<0 || i>=m || j>=n) return;
    else
    {
        map[i][j]='*';//扫过的都变成'*'
        dfs(i-1, j-1);
        dfs(i-1, j);
        dfs(i-1, j+1);
        dfs(i, j-1);
        dfs(i, j+1);
        dfs(i+1, j-1);
        dfs(i+1, j);
        dfs(i+1, j+1);
    }
}
int main()
{
    int i, j;
    while(scanf("%d%d",&m,&n)!=EOF)
    {
        if(m==0 || n==0) break;
        p = 0;
        for(i = 0; i < m; i++)
            for(j = 0; j < n; j++)
            //scanf("%c",&map[i][j]);
                cin>>map[i][j];
        for(i = 0; i < m; i++)
        {
            for(j = 0; j < n; j++)
            {
                if(map[i][j] == '@')
                {
                    dfs(i, j);
                    p++;
                }
            }
        }
        printf("%d\n",p);
    }

    return 0;
}