题目如下：

Oil Deposits

The GeoSurvComp geologic survey company is responsible for detectingunderground oil deposits. GeoSurvComp works with one large rectangularregion of land at a time, and createsa grid that divides the land into numerous square plots. It then analyzeseach plot
separately,using sensing equipment to determine whether or not the plot contains oil.

A plot containingoil is called a pocket. If two pockets are adjacent, then they are part ofthe same oil deposit. Oildeposits can be quite large and may contain numerous pockets. Your job is todetermine how many different oil deposits are contained in a grid.

Input

The input file contains one or more grids. Each grid begins with a linecontaining
m and n, thenumber of rows and columns in the grid, separated by a single space. Ifm = 0 it signals the endof the input; otherwise
and
.Followingthis are
m lines of n characterseach (not counting the end-of-line characters). Each character corresponds toone plot, and iseither `*‘, representing the absence of oil, or `@‘, representing an oil pocket.

Output

For each grid, output the number of distinct oil deposits. Two differentpockets are part of thesame 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

求连块的个数，图的深度优先搜索。

AC的代码如下：

UVA Oil Deposits,布布扣,bubuko.com