广度优先算法走出迷宫

广度优先算法（Breadth-First Search），同广度优先搜索，又称作宽度优先搜索，或横向优先搜索，简称BFS，是一种图形搜索演算法。简单的说，BFS是从根节点开始，沿着树的宽度遍历树的节点，如果发现目标，则演算终止。广度优先搜索的实现一般采用open-closed表。

有这么一个迷宫:

6 5
0 1 0 0 0
0 0 0 1 0
0 1 0 1 0
1 1 1 0 0
0 1 0 0 1
0 1 0 0 0

其中第一行6代表行数，5代表列表，0代表可以走的路线。1代表墙壁。
假想有一个x轴和y轴， 开始位置: 0,0 终点位置: 6,5
用程序实现最短的路线如下:

package main

import (
	"fmt"
	"os"
)

func readMaze(filename string) [][]int {
	file, err := os.Open(filename)
	if err != nil {
		panic(err)
	}
	var row, col int
	fmt.Fscanf(file, "%d %d", &row, &col)

	maze := make([][]int, row)
	for i := range maze {
		maze[i] = make([]int, col)
		for j := range maze[i] {
			fmt.Fscanf(file, "%d", &maze[i][j])
		}
	}
	return maze
}

type point struct {
	i, j int
}

var dirs = [4]point{
	{-1, 0},{0, -1},{1, 0},{0, 1},
}

func (p point) add(r point) point {
	return point{p.i + r.i, p.j + r.j }
}

func (p point) at(grid [][]int) (int, bool) {
	if p.i < 0 || p.i >= len(grid) {
		return 0, false
	}

	if p.j < 0 || p.j >= len(grid[p.i]) {
		return 0, false
	}

	return grid[p.i][p.j], true
}

func walk(maze [][]int, start, end point) [][]int {
	steps := make([][]int, len(maze))
	for i := range steps {
		steps[i] = make([]int, len(maze[i]))
	}

	Q := []point{start}

	for len(Q) > 0 {
		cur := Q[0]
		Q = Q[1:]

		if cur == end {
			break
		}
		for _, dir := range dirs {
			next := cur.add(dir)

			val, ok := next.at(maze)
			if !ok || val == 1 {
				continue
			}

			val, ok = next.at(steps)
			if !ok || val != 0 {
				continue
			}

			if next == start {
				continue
			}

			curSteps, _ := cur.at(steps)
			steps[next.i][next.j] = curSteps + 1
			Q = append(Q, next)
		}
	}
	return steps
}

func main() {
	maze := readMaze("./maze.in")
	for i := range maze {
		for _, j := range maze[i] {
			fmt.Printf("%3d", j)
		}
		fmt.Println()
	}
	fmt.Println()
	steps := walk(maze, point{0,0},point{len(maze) - 1, len(maze[0]) - 1})

	for _, row := range steps {
		for _, val := range row {
			fmt.Printf("%3d", val)
		}
		fmt.Println()
	}
}

golang数据结构：
https://github.com/Workiva/go-datastructures
https://github.com/emirpasic/gods