有趣的 ponds and islands 递归

yorkzjy 2010-02-04 02:14:55

今天在教室的黑板上看到了这个题目，觉得挺有趣。
：
给出一个矩阵，即通 ponds 或者 islands 的个数，相连的 0 为一个pond ，相连的 1 为一个island。
（其实跟找迷宫差不多）
这是我写的递归程序，可是得不到正确答案。请高手指教我错在哪里了？？

数据：每个矩阵开头一行是说明列行大小的

5 5
0 1 0 1 0
0 1 0 1 0
0 0 0 1 0
1 1 0 0 1
0 0 0 1 0
6 10
0 0 0 1 0 0 1 0 1 0
1 1 0 1 1 0 1 0 1 0
0 0 0 0 0 0 0 0 0 0
1 1 1 0 1 1 1 0 1 1
0 0 0 0 1 1 1 0 1 0
1 1 1 0 0 0 0 0 0 0
10 10
0 0 0 0 1 0 0 0 0 0
1 1 0 1 1 1 1 0 1 1
0 0 0 0 1 0 0 0 0 0
1 0 0 0 1 1 1 1 0 1
0 0 0 0 0 1 0 0 0 0
1 0 0 0 1 1 1 0 1 1
0 0 0 0 0 0 0 0 0 0
1 1 1 1 1 1 1 1 1 1
0 0 0 0 0 0 0 1 1 0
0 1 0 1 0 1 0 0 0 0
6 6
0 1 1 1 1 1
0 0 0 0 0 0
1 1 1 0 1 1
0 0 0 0 1 1
1 0 1 1 1 1
0 0 0 0 1 0
4 4
1 1 1 1
1 1 1 1
1 1 1 1
1 1 1 1
4 4
1 0 1 0
0 1 0 1
1 0 1 0
0 1 0 1
20 20
0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0
1 1 1 1 1 0 1 1 1 1 1 1 1 0 1 1 1 1 1 1
0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 1 1 1 0
1 1 1 1 1 1 1 1 1 1 1 1 0 1 1 0 1 1 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1
0 1 0 0 0 0 0 1 0 1 0 1 0 1 0 1 0 1 0 1
0 1 1 0 1 1 0 1 1 1 0 1 0 0 1 0 0 1 1 0
0 0 0 0 1 0 0 0 0 0 0 1 1 1 1 1 1 1 1 0
1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 1 1 1 1 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 1 1 1 0 1 1 1 1 1 0 1 1 1 0 1 1 1 1 1
0 0 0 0 0 0 1 1 1 1 1 1 1 1 0 1 1 1 1 1
0 1 1 1 1 1 0 0 0 0 1 1 1 1 0 1 1 1 1 1
0 0 0 0 0 0 0 1 0 1 1 0 0 0 0 0 0 0 0 1
1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 0 1 1
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0 1 0



#include <iostream>

#include <fstream>

#include <sstream>

#include <string>

using namespace std;



typedef struct node

{

    int data;// 0 for island 1 for pond

    bool visited;



}node;



void recMark(node **Matrix, int y, int x, int flag)//rec find and mark

{

    Matrix[y][x].visited = true;

    if(Matrix[y-1][x].data = flag)

        recMark(Matrix, y-1, x, flag);

    if(Matrix[y][x+1].data = flag)

        recMark(Matrix, y, x+1, flag);

    if(Matrix[y+1][x].data = flag)

        recMark(Matrix, y+1, x, flag);

    if(Matrix[y][x-1].data = flag)

        recMark(Matrix, y, x-1, flag);







}



void loopFind(node **Matrix, int y , int x)//y and x represent the size of the matrix

{

    int pondCounts = 0;

    int islandCounts = 0;

    for(int _y = 1; _y <= y-2; _y++ )

    {

        for(int _x = 1; _x <= x-2 ; _x++)

        {

            if(Matrix[_y][_x].visited == false)//if not visited, then visit all related

            {

                if(Matrix[_y][_x].data == 0)

                {

                    recMark(Matrix, _y, _x, 0);

                    pondCounts++;

                }

                else if(Matrix[_y][_x].data == 1)

                {

                    recMark(Matrix, _y, _x, 1);

                    islandCounts++;



                }

            }

        }

    }

    cout<<"the number of pond: "<<pondCounts<<", and the number of island(s): "<<islandCounts<<endl;



    //return tolCounts;

}





int main()

{

    ifstream fin;

    fin.open("PondsIslands.txt");

    if(!fin)

    {

        cout<<"opening file failed"<<endl;

        exit(-1);

    }

    int x =0;

    int y =0;

    while(!fin.eof())

    {

        fin>>y>>x;

        node theMatrix[y+2][x+2];

        for(int _x = 0;_x<x+2; _x++ )

        {

            for(int _y = 0; _y< y+2; _y++ )

            {

                theMatrix[y][x].visited = false; // mark un-visited

            }

        }

        //setting the surrounding to 9 to signify edging

        for(int temp = 0; temp < x+2; temp++)

        {

            theMatrix[0][temp].data = 9;

            theMatrix[y+1][temp].data = 9;







        }

        for(int temp = 0; temp < y+2; temp++)

        {

            theMatrix[temp][0].data = 9;

            theMatrix[temp][x+1].data = 9;

        }

        //putting all the number 0 or 1 into the inner of array

        for(int tempY = 1; tempY <= y; tempY++)

        {

            for(int tempX = 1; tempX<= x; tempX++)

            {

                string stemp;

                getline(fin, stemp);

                stringstream sstemp(stemp);

                sstemp>>theMatrix[tempX][tempY].data;



            }

        }



    //cout<<"reach here "<<endl;



    }

    fin.close();



    return 0;





}