BFS求解迷宫

Posted on | In , |

bfs 广度优先遍历

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
#include <cstdio>
#include <iostream>
#include <queue>
#include <stack>
using namespace std;

const int MaxN = 105;
int n, m;
int maze[MaxN][MaxN];
bool vis[MaxN][MaxN];
int fa[MaxN][MaxN], dist[MaxN][MaxN], last_dir[MaxN][MaxN];

///u, d, l, r
int dx[4] = {0, 0, -1, 1};
int dy[4] = {1, -1, 0, 0};
char name[4] = {'r', 'l', 'u', 'd'};

bool inbound(int x, int l, int r)
{
	if (x >= l)
		if (x < r)
			return true;
		else
			return false;
	else
		return false;
}

void bfs(int x, int y)
{
    int d = 0;
    int u = x * m + y;
    vis[x][y] = 1;
    fa[x][y] = u;
    dist[x][y] = 0;
    queue<int> q;
    q.push(u);
    while (!q.empty())
    {
        u = q.front(); q.pop();
        x = u / m; y = u % m;
        for (d = 0; d < 4; d++)
        {
            int nx = x + dx[d];
            int ny = y + dy[d];
            if (inbound(nx, 0, n) && inbound(ny, 0, m)
                && maze[nx][ny] && !vis[nx][ny])
            {
                int v = nx * m + ny;
                q.push(v);
                vis[nx][ny] = 1;
                fa[nx][ny] = u;
                //cout<<"fa:"<<" nx:"<<nx<<" ny:"<<ny<<"  u:"<<u<<endl; 
                dist[nx][ny] = dist[x][y] + 1;
                last_dir[nx][ny] = d;
               // cout<<"dir: "<<d<<endl;
            }
        }
    }
    
    return;
}

void init()
{
    freopen("maze.in", "r", stdin);
    scanf("%d%d", &n, &m);
    for (int i = 0; i < n; i++)
        for (int j = 0; j < m; j++)
            scanf("%d", &maze[i][j]);
    puts("打印迷宫：");
    printf("i \\ j   ");
    for (int j = 0; j < m; j++)
        printf("%7d:", j);
    printf("\n");
    for (int i = 0; i < n; i++)
    {
        printf("%4d:   ", i);
        for (int j = 0; j < m - 1; j++)
            printf("%8d", maze[i][j]);
        printf("%8d\n", maze[i][m - 1]);
    }
    puts("输入终点坐标");
    bfs(0, 0);
}

void print(int x, int y)
{
    stack<int> dir;
    cout<<endl;
    while (true)
    {
        int fx = fa[x][y] / m;
        int fy = fa[x][y] % m;
       // cout<<" fx:"<fx<<" fy:"<<fy<<endl;
        //cout<<" x:"<<x<<" y:"<<y<<endl;
        if (fx == x && fy == y) break;
        dir.push(last_dir[x][y]);
        x = fx; y = fy;
    }
    while (!dir.empty())
    {
        printf("%c", name[dir.top()]);
        dir.pop();
    }
}

int main()
{
    init();
    freopen("CON", "r", stdin);
    int sx, sy;
    scanf("%d%d", &sx, &sy);
//    sx=3;
//    sy=3;
	print(sx, sy);
    return 0;
}

image
参考链接
https://blog.csdn.net/s_lisheng/article/details/73799880