The Simplest Maze - (DFS&BFS Preliminary Learning)

describe:

Given the maze, the starting point and the ending point, find the shortest distance from the starting point to the ending point, (you can only walk up and down, left and right, one grid distance 1)

DFS

#include <iostream>
#include <algorithm>

using namespace std;
                           //Maze, x,y start from (1,1),  
int minn = 0x3f3f3f3f;
int next[4][2] = {{0,1},{1,0},{0,-1},{-1,0}}; //The direction coordinates are right, down, left, up
int a[50][50];
int book[50][50];
int n,m;
int sx, sy, ex, ey;

void DFS(int x,int y,int step) //The current position, the number of steps taken
{
	if(x == ex && y == ey) // if it has arrived, compare the number of steps
	{
		if(step < minn)
			minn = step;
		return;
	}
	for(int i = 0;i < 4;i++) //There are four directions to choose from each step
	{
		int nx = x + next[i][0];
		int ny = y + next[i][1]; //The coordinates of the next step.
		
		if(nx <1 || nx > n || ny < 1 || ny > m) // if out of bounds
			continue;
		
		if(a[nx][ny] == 0 && book[nx][ny] == 0) //if the point is not an obstacle and is not in the path.
		{
			book[nx][ny] = 1; //mark this point
			DFS(nx,ny,step + 1); //Start trying the next point
			book[nx][ny] = 0; //The end of the attempt, cancel the mark of this point, the following is the next direction
		}
	}
	return;
}

intmain()
{
	
	
	cin>>n>>m;
	for(int i = 1;i <= n;i ++)
	{
		for(int j = 1;j <= m;j ++)
		{
			cin>>a[i][j];
		}
	}
	cin>>sx>>sy>>ex>>ey;
	DFS (sx, sy, 0);
	cout<<minn<<endl;
	return 0;
}

BFS

#include <iostream>
#include <algorithm>
#include <queue>

using namespace std;

struct Note
{
	int x; //abscissa
	int y; // ordinate
	int s; // number of steps
 };
Rating N;
queue<Note> q;
int a[51][51]; //Store the map
int book[51][51] = {0};

int next[4][2] = {{0,1},
				  {1,0},
				  {0,-1},
				  {-1,0}};
int n,m;
int sx, sy, ex, ey;
int flag;
intmain()
{
	int nx,ny;//The coordinates of the next point
	scanf("%d %d",&n,&m);
	for(int i = 1;i <= n;i ++)
	{
		for(int j = 1;j <= m;j ++)
			scanf("%d",&a[i][j]);
	}
	scanf("%d %d %d %d",&sx,&sy,&ex,&ey);
	N.x = sx;
	The = and;
	N.s = 0;
	q.push(N);//Add the starting point to the queue first
	book[sx][sy] = 1; //The starting point has been visited
	
	flag = 0; // mark whether to reach the target point
	
	while(!q.empty()) //When the queue is not empty
	{
		for(int i = 0;i < 3;i++) //four directions
		{
			N.x = q.front().x + next[i][0];
			Ny = q.front().y + next[i][1]; //The coordinates of the new point
			// Determine whether it is out of bounds
			if(N.x < 1 || N.x > n || N.y < 1 || N.y > n)
				continue;
			/ / Determine whether it is an obstacle or has been in the path
			if(a[N.x][N.y] == 0 && book[N.x][N.y] == 0)
			{
				book[N.x][N.y] = 1;
				// new point is added to the queue
				N.s = q.front().s + 1;
				q.push(N);
			}
			if(N.x == ex && N.y == ey)
			{
				flag = 1;
				break;
			 }
		}
		
		if(flag == 1)
			break;
		q.pop(); //The four directions of a point have been judged, delete the team leader, and then expand	
	}
	
	printf("%d\n",q.back().s);
	return 0;
 }