Mazo.go

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}

}

// at returns the point wether is in the grid and value

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 {

	// walked path

	steps := make([][]int, len(maze))

	for i := range steps {

		steps[i] = make([]int, len(maze[i]))

	}

	// queue

	Q := []point{start}

	for len(Q) > 0 {

		cur := Q[0]

		Q = Q[1:]

		if cur == end {

			// reach the end

			break

		}

		for _, dir := range dirs {

			next := cur.add(dir)

			// maze at next is 0

			// and steps at next is 0

			// and next != start

			val, ok := next.at(maze)

			if !ok || val == 1 {

				continue

			}

			//next never pass

			val, ok = next.at(steps)

			if !ok || val != 0 {

				continue

			}

			if next == start {

				continue

			}

			//cur which step

			curSteps, _ := cur.at(steps)

			// record the next's step

			steps[next.i][next.j] = curSteps + 1

			Q = append(Q, next)

		}

	}

	return steps

}

func main() {

	maze := readMaze("Hacktoberfest-2022/Maze.in")

	for _, row := range maze {

		for _, val := range row {

			fmt.Printf("%d ", val)

		}

		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()

	}

}