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递归查找矩阵连通域

零式的天空

发布于 2022-03-22 02:54:15

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代码可运行

文章被收录于专栏：零域Blog零域Blog

运行总次数：0

代码可运行

题目的来源是给定一张图片，查找所有临近的像素点，并求出最大像素值。经过抽象后是：两个矩阵，一个只是包含0 1,另一个是每个位置具体的像素值，可以通过查找第一个矩阵来确定连通域的点，根据第二个矩阵得出最大的值。

矩阵1：

# data
1 0 0 0 1 0 0 0 0 1
0 1 0 0 1 0 0 0 0 0
0 1 1 0 1 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1
0 0 0 0 1 0 0 0 0 0
0 0 0 1 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 1 0 0 0
0 0 0 0 0 0 1 1 1 0
0 0 0 0 0 0 0 0 0 1
1 0 0 0 1 0 0 0 0 1
0 1 0 0 1 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0
0 1 0 0 1 0 0 0 0 0

矩阵2：

# data2
1 0 0 0 1 0 0 0 0 1
0 2 0 0 3 0 0 0 0 0
0 1 1 0 1 0 0 0 0 0
0 0 0 0 0 0 0 0 0 1
0 0 0 0 4 0 0 0 0 0
0 0 0 1 0 0 0 0 0 0
1 0 0 0 0 0 0 0 0 0
0 0 0 0 0 1 1 0 0 0
0 0 0 0 0 0 5 1 1 0
0 0 0 0 0 0 0 0 0 1
1 0 0 0 1 0 0 0 0 1
0 6 0 0 1 0 0 0 0 0
0 0 0 0 0 0 0 1 0 0
0 7 0 0 8 0 0 0 0 0

C++代码为：

// recursionFindPoints.cpp

#include <stdlib.h>
#include <iostream>
#include <fstream>
#include <sstream>
#include <string>
#include <utility>
#include <vector>

using namespace std;

typedef long long ll;
typedef double    db;

long flag = 2;
long START = flag;

int recursion(ll i, ll j, vector<vector<ll> > &data, vector<pair<ll,ll> > &position);
int launch( vector<vector<ll> > &data, vector<vector<db> > &data2);

int main(int argc, char * argv[])
{
    if (argc != 3)
    {
        cout<<"Enter two file"<<endl;
        return -1;
    }
    // 1 read map and intensity
    ifstream fin(argv[1]);
    ifstream fin2(argv[2]);

    vector<vector<ll> > data;
    vector<vector<db> > data2;
    vector<ll> temp;
    ll v;
    vector<db> temp2;
    db d;

    string line;
    string value;
    while (getline(fin,line))
    {
        stringstream ss(line);
        while (getline(ss,value,' '))
        {
           v = atoi(value.c_str());  
           temp.push_back(v);
        }
        data.push_back(temp);
        temp.clear();
    }	

    while (getline(fin2,line))
    {
        stringstream ss(line);
        while (getline(ss,value,' '))
        {
           d = atoi(value.c_str());  
           temp2.push_back(d);
        }
        data2.push_back(temp2);
        temp2.clear();
    }	

    // 2 entrance
    launch(data,data2);

    // 3 output result
    for (vector<vector<ll> >::iterator it = data.begin(); it != data.end(); ++it)
    {
        for (vector<ll>::iterator i = (*it).begin(); i != (*it).end(); ++i)
            cout<<*i<<" ";
        cout<<endl;
    }

}

int launch(vector<vector<ll> > &data, vector<vector<db> > &data2)
{
    // 1. Find all points in connected domain and store these coordinate
    vector<vector<pair<ll,ll> > > result;
    vector<pair<ll,ll> >  temp;
    for (int i = 0; i < data.size(); ++i)
    {
        for (int j = 0; j < data[0].size(); ++j)
        {
            if (data[i][j] == 1)
            {
               temp.push_back(make_pair(i,j)); 
               data[i][j] = flag;
               recursion(i,j,data,temp);
               flag++;
               result.push_back(temp);
               temp.clear();
            }
        }
    }

    // 2. Filter
    pair<ll,ll> pos;
    db inten = 0;
    for (vector<vector<pair<ll,ll> > >::iterator it = result.begin(); it != result.end(); ++it)
    {
        for (vector<pair<ll, ll> >::iterator jt = (*it).begin(); jt != (*it).end(); ++jt)
        {
            // cout<<(*jt).first<<" "<<(*jt).second<<"    ";
            if (inten <= data2[(*jt).first][(*jt).second])
            {
                inten = data2[(*jt).first][(*jt).second];
                pos.first = (*jt).first;
                pos.second = (*jt).second;
            }
        }
        // cout<<endl;
        printf("The %d points's max intensity is: %d\n", int(START), int(inten));
        START ++;
        inten = 0;
    }

    return 0;
}

int recursion(ll i, ll j, vector<vector<ll> > &data, vector<pair<ll,ll> > &position)
{
    for (int x = i - 1; x <= i + 1; x++)
    {
        for (int y = j - 1; y <= j + 1; y++)
        {
            if (x == i && y == j)
                continue;
            if (x >= 0 && x < data.size() && y >= 0 && y < data[0].size() && data[x][y] == 1)
            {
                position.push_back(make_pair(x, y));
                data[x][y] = flag;
                recursion(x,y,data,position);
            }
        }
    }
    return 0;
}

运行程序及结果：

$ g++ recursionFindPoints.cpp -o rfp
$ ./rfp data data2
The 2 points's max intensity is: 2
The 3 points's max intensity is: 3
The 4 points's max intensity is: 1
The 5 points's max intensity is: 1
The 6 points's max intensity is: 4
The 7 points's max intensity is: 1
The 8 points's max intensity is: 5
The 9 points's max intensity is: 6
The 10 points's max intensity is: 1
The 11 points's max intensity is: 1
The 12 points's max intensity is: 7
The 13 points's max intensity is: 8
2 0 0 0 3 0 0 0 0 4 
0 2 0 0 3 0 0 0 0 0 
0 2 2 0 3 0 0 0 0 0 
0 0 0 0 0 0 0 0 0 5 
0 0 0 0 6 0 0 0 0 0 
0 0 0 6 0 0 0 0 0 0 
7 0 0 0 0 0 0 0 0 0 
0 0 0 0 0 8 8 0 0 0 
0 0 0 0 0 0 8 8 8 0 
0 0 0 0 0 0 0 0 0 8 
9 0 0 0 10 0 0 0 0 8 
0 9 0 0 10 0 0 0 0 0 
0 0 0 0 0 0 0 11 0 0 
0 12 0 0 13 0 0 0 0 0