## maze - dfs

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``````6 5

0 1 0 0 0

0 0 0 1 0
0 1 1 1 0
1 1 0 0 0
0 1 0 1 1
0 1 0 0 0
``````

go:

``````package main

import (
"fmt"
"os"
)

type point struct {
i, j int
val  int
}

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

// 判断点是否出界
func (p point) at(grid [][]int) (int, bool) {
if p.i < 0 || p.i >= len(grid) || p.j < 0 || p.j >= len(grid[0]) {
return 0, false
}
return grid[p.i][p.j], true
}

var dirs = []point{{i: -1, j: 0}, {i: 1, j: 0}, {i: 0, j: -1}, {i: 0, j: 1}}

func walk(maze [][]int, start, end point) [][]int {
var steps = make([][]int, len(maze)) // 记录走到当前位置的最小步数
for i := range steps {
steps[i] = make([]int, len(maze[0]))
}

queue := []point{start}

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

if cur == end {
break
}

for _, dir := range dirs {

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

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

if next == start {
continue
}

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

}

return steps
}

file, err := os.Open(fileName)
if err != nil {
panic(err)
}

var row, col int
_, _ = fmt.Fscanf(file, "%d %d", &row, &col)

var maze = make([][]int, row)
for i := range maze {
maze[i] = make([]int, col)
for j := range maze[i] {
_, _ = fmt.Fscan(file, &maze[i][j])
}
}

return maze
}

func main() {
start := point{i: 0, j: 0}
end := point{i: len(maze), j: len(maze[0])}

steps := walk(maze, start, end)

var res = make([][]int, len(maze)) // 记录走到当前位置的最小步数
for i := range steps {
res[i] = make([]int, len(maze[0]))
}

i := end.i - 1
j := end.j - 1
res[i][j] = 1
for !(i == start.i && j == start.j) {
for _, dir := range dirs {
nextI, nextJ := dir.i+i, dir.j+j
if nextI < 0 || nextI >= len(steps) || nextJ < 0 || nextJ >= len((steps)[0]) {
continue
}
if steps[nextI][nextJ] == steps[i][j]-1 {
i, j = nextI, nextJ
res[nextI][nextJ] = 1
break
}
}
}

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

}

``````