计算水池数目

原题目链接：原题目

采用广度优先算法来做

为了简单起见，不从标准输入读取数据，数据在代码中指定

代码如下：

 1 #include <iostream>

 2 #include <list>

 3 using namespace std;

 4 #define COLUMN_NUMBER 5

 5 #define ROW_NUMBER 5

 6 

 7 int get_count(const int (*data)[COLUMN_NUMBER]);

 8 

 9 struct Point {

10     int x;

11     int y;

12     Point(int x,int y)

13     {

14         this->x = x;

15         this->y = y;

16     }

17     Point(){}

18 

19 };

20 

21 int main()

22 {

23     int data[ROW_NUMBER][COLUMN_NUMBER] = {{1,1,1,1,0},

24                                           {0,0,1,0,1},

25                                           {0,0,0,0,0},

26                                           {1,1,1,0,0},

27                                           {0,0,1,1,1}};

28     int count = get_count(data);

29     cout << "count = " << count << endl;

30     return 0;

31 }

32 

33 

34 int get_count(const int (*data)[COLUMN_NUMBER])

35 {

36     int count = 0;

37     int is_travelled[ROW_NUMBER][COLUMN_NUMBER] = {0};

38 

39     for(int i = 0;i < ROW_NUMBER;++i)

40     {

41         for(int j = 0;j < COLUMN_NUMBER;++j)

42         {

43             //if it is a pool and is has not been travelled

44             if(1 == data[i][j] && 0 == is_travelled[i][j])

45             {

46                 ++count;

47 

48                 is_travelled[i][j] = 1;//make it been travelled

49                 list<Point> vec;

50                 Point p(i,j);

51                 vec.push_back(p);

52                 while(!vec.empty())

53                 {

54                     Point current_point = vec.front();//get the first element

55                     vec.erase(vec.begin());//delete the first element

56                     //get the four neighor coordinates

57                     int left_top_x = current_point.x == 0 ? 0 : current_point.x -1 ;

58                     int left_top_y = current_point.y == 0 ? 0 : current_point.y - 1;

59                     int right_bottom_x = current_point.x == ROW_NUMBER - 1 ? ROW_NUMBER - 1 : current_point.x + 1;

60                     int right_bottom_y = current_point.y == COLUMN_NUMBER - 1 ? COLUMN_NUMBER - 1 : current_point.y + 1;

61 

62                     Point vertex[4];

63                     vertex[0] = Point(left_top_x,current_point.y);

64                     vertex[1] = Point(right_bottom_x,current_point.y);

65                     vertex[2] = Point(current_point.x,left_top_y);

66                     vertex[3] = Point(current_point.x,right_bottom_y);

67 

68                     for(int i = 0; i < 4;++i)

69                     {

70                         Point _p = vertex[i];

71                         if(0 == is_travelled[_p.x][_p.y] && 1 == data[_p.x][_p.y])

72                             vec.push_back(_p);

73                         is_travelled[_p.x][_p.y] = 1;

74                     }

75                 }

76             }

77         }

78     }

79 

80     return count;

81 

82 }