maze.js

var assert = require('assert')


var maze = [  
  [1,0,1,1,0],
  [1,0,1,0,0],
  [1,0,0,0,0],
  [1,0,0,0,0] 
]

// http://www.cnblogs.com/biyeymyhjob/archive/2012/07/31/2615833.html

assert.equal(path(maze, [0, 1], [1, 3]), 6);

//https://en.wikipedia.org/wiki/A*_search_algorithm

function path(maze, start, end){
   
   return bfs(maze, start, end)
}

function bfs(maze, start, end){
  
   var result = 0
   
   var queue = []
   queue.push(start)
   maze[start[0]][start[1]] = '2'
   
   while(queue.length > 0){
     
     var size = queue.length
     result++
           
     for(var i = 0; i < size; i++){
       var node = queue.shift()
     
       if(node[0] === end[0] && node[1] === end[1]) return result

       if(walkable(maze, node[0] + 1,  node[1])) queue.push([node[0] + 1,  node[1]]) 
       if(walkable(maze, node[0] - 1,  node[1])) queue.push([node[0] - 1,  node[1]]) 
       if(walkable(maze, node[0],  node[1] + 1)) queue.push([node[0],  node[1] + 1]) 
       if(walkable(maze, node[0],  node[1] - 1)) queue.push([node[0],  node[1] - 1])  
      }
   }
   
   return result 
}

function walkable(maze, x, y){
  if (maze[x] === undefined || maze[x][y] === undefined) return false //out of bounce
  if (maze[x][y] === 1) return false //unwalkable
  if (maze[x][y] === 2) return false //visited
  
  maze[x][y] = 2
  return true
}

//