深度优先搜索DFS,广度优先搜索BFS, 遍历矩阵

深度优先搜索DFS,用递归,相当于先序遍历
广度优先搜索BFS, 用队列, push进去的时候访问,标记

#include <iostream>
#include <vector>
#include <queue>

using namespace std;

struct axis
{
    
    
    axis() : x(-1), y(-1) {
    
    }
    axis(int x_, int y_) : x(x_), y(y_) {
    
    }
    int x;
    int y;
};

void DFS(vector<vector<int>> &MAT, int i, int j);
void BFS(vector<vector<int>> &MAT, int i, int j);

int main()
{
    
    
    vector<vector<int>> MAT{
    
    {
    
    1, 2, 3, 4, 5, 0, 0},
                            {
    
    6, 7, 8, 9, 0, 0, 10},
                            {
    
    0, 0, 11, 12, 13, 14, 0},
                            {
    
    0, 15, 16, 0, 0, 17, 18},
                            {
    
    19, 20, 0, 0, 0, 24, 0}};

    DFS(MAT, 2, 3);
    BFS(MAT, 2, 3);
    return 0;
}

//深度优先,用递归,相当于先序遍历
void DFS(vector<vector<int>> &MAT, int i, int j)
{
    
    
    int row = MAT.size();
    int col = MAT[0].size();
    cout << i << " " << j << " " << MAT[i][j] << endl;
    MAT[i][j] = -1;
    if (i - 1 >= 0 && j >= 0 && i - 1 < row && j < col && MAT[i - 1][j] != -1)
        DFS(MAT, i - 1, j);
    if (i + 1 >= 0 && j >= 0 && i + 1 < row && j < col && MAT[i + 1][j] != -1)
        DFS(MAT, i + 1, j);
    if (i >= 0 && j - 1 >= 0 && i < row && j - 1 < col && MAT[i][j - 1] != -1)
        DFS(MAT, i, j - 1);
    if (i >= 0 && j + 1 >= 0 && i < row && j + 1 < col && MAT[i][j + 1] != -1)
        DFS(MAT, i, j + 1);
}

//广度优先搜索, 用队列, push进去的时候访问,标记
void BFS(vector<vector<int>> &MAT, int i, int j)
{
    
    
    int row = MAT.size();
    int col = MAT[0].size();
    queue<axis> QUEUE;
    QUEUE.push(axis(i, j));
    cout << i << " " << j << " " << MAT[i][j] << endl;
    MAT[i][j] = -1;
    axis front;
    int x, y;

    while (!QUEUE.empty())
    {
    
    
        front = QUEUE.front();
        QUEUE.pop();
        x = front.x;
        y = front.y;
        if (x - 1 >= 0 && x - i < row && MAT[x - 1][y] != -1)
        {
    
    
            QUEUE.push(axis(x - 1, y));
            cout << x - 1 << " " << y << " " << MAT[x - 1][y] << endl;
            MAT[x - 1][y] = -1;
        }
        if (x + 1 >= 0 && x + 1 < row && MAT[x + 1][y] != -1)
        {
    
    
            QUEUE.push(axis(x + 1, y));
            cout << x + 1 << " " << y << " " << MAT[x + 1][y] << endl;
            MAT[x + 1][y] = -1;
        }
        if (y - 1 >= 0 && y - 1 < col && MAT[x][y - 1] != -1)
        {
    
    
            QUEUE.push(axis(x, y - 1));
            cout << x << " " << y - 1 << " " << MAT[x][y - 1] << endl;
            MAT[x][y - 1] = -1;
        }
        if (y + 1 >= 0 && y + 1 < col && MAT[x][y + 1] != -1)
        {
    
    
            QUEUE.push(axis(x, y + 1));
            cout << x << " " << y + 1 << " " << MAT[x][y + 1] << endl;
            MAT[x][y + 1] = -1;
        }
    }
}