7-1 迷宫_算法

1635333441923
1635333456976

7-2 迷宫代码实现

  1. 6 5
  2. 0 1 0 0 0
  3. 0 0 0 1 0
  4. 0 1 0 1 0
  5. 1 1 1 0 0
  6. 0 1 0 0 1
  7. 0 1 0 0 0
  1. package main
  3. import (
  4.     "fmt"
  5.     "os"
  6. )
  8. func readMaze(filename string) [][]int {
  9.     file, err := os.Open(filename)
  10.     if err != nil {
  11.         panic(err)
  12.     }
  14.     var row, col int
  15.     fmt.Fscanf(file, "%d %d", &row, &col)
  17.     maze := make([][]int, row)
  18.     for i := range maze {
  19.         maze[i] = make([]int, col)
  20.         for j := range maze[i] {
  21.             fmt.Fscanf(file, "%d", &maze[i][j])
  22.         }
  23.     }
  25.     return maze
  26. }
  28. type point struct {
  29.     i, j int
  30. }
  32. var dirs = [4]point{
  33.     {-1, 0}, {0, -1}, {1, 0}, {0, 1}}
  35. func (p point) add(r point) point {
  36.     return point{p.i + r.i, p.j + r.j}
  37. }
  39. func (p point) at(grid [][]int) (int, bool) {
  40.     if p.i < 0 || p.i >= len(grid) {
  41.         return 0, false
  42.     }
  44.     if p.j < 0 || p.j >= len(grid[p.i]) {
  45.         return 0, false
  46.     }
  48.     return grid[p.i][p.j], true
  49. }
  51. func walk(maze [][]int,
  52.     start, end point) [][]int {
  53.     steps := make([][]int, len(maze))
  54.     for i := range steps {
  55.         steps[i] = make([]int, len(maze[i]))
  56.     }
  58.     Q := []point{start}
  60.     for len(Q) > 0 {
  61.         cur := Q[0]
  62.         Q = Q[1:]
  64.         if cur == end {
  65.             break
  66.         }
  68.         for _, dir := range dirs {
  69.             next := cur.add(dir)
  71.             val, ok := next.at(maze)
  72.             if !ok || val == 1 {
  73.                 continue
  74.             }
  76.             val, ok = next.at(steps)
  77.             if !ok || val != 0 {
  78.                 continue
  79.             }
  81.             if next == start {
  82.                 continue
  83.             }
  85.             curSteps, _ := cur.at(steps)
  86.             steps[next.i][next.j] =
  87.                 curSteps + 1
  89.             Q = append(Q, next)
  90.         }
  91.     }
  93.     return steps
  94. }
  96. func main() {
  97.     maze := readMaze("lang/maze/maze.in")
  99.     steps := walk(maze, point{0, 0},
  100.         point{len(maze) - 1, len(maze[0]) - 1})
  102.     for _, row := range steps {
  103.         for _, val := range row {
  104.             fmt.Printf("%3d", val)
  105.         }
  106.         fmt.Println()
  107.     }
  109.     // TODO: construct path from steps
  110. }