廣度優先搜索Javascript（算法或輸入）

Question

它只是被認為是廣度優先搜索，並在此過程中標記了父母。 當它完成時，它會追溯那些父母回到起點。

地圖只是這些圖塊的數組

function Tile(x, y){

    this.x = x;
    this.y = y;

    //for BFS
    this.px = 0;
    this.py = 0;
    this.visited = false;

    this.is = " ";

    this.n = null;
    this.e = null;
    this.s = null;
    this.w = null;
}

我一生都無法確定是我的算法還是我的起始數據。

如果有人可以幫助我解決此對象或將其清除為正確的狀態，我將不勝感激。

    function FakeBFS(){
    var me = this;

    this.get_path = function(sx, sy, ex, ey, map){
        var x = sx;
        var y = sy;
        var unfinished = [{"x":sx, "y":sy}];

        //walk until we can't or we reach our destination
        while(unfinished.length && x != ex && y != ey){

            var new_location = unfinished.shift();

            x = new_location.x;
            y = new_location.y;

            //if we haven't been here...
            if(map.tiles[x][y].visited == false){

                console.log("\n\nlooking for path from:"+x+","+y+" to:"+ex+","+ey);
                var nesw_array = new Array(
                                            [x,y+1], //n
                                            [x+1,y], //e
                                            [x,y-1], //s
                                            [x-1,y]);//w
                                            console.log(nesw_array);

                //add all the vertices we care about to unfinished
                for(var nesw=0; nesw<4; nesw++){
                    var vx = nesw_array[nesw][0];
                    var vy = nesw_array[nesw][1];
                    console.log(nesw_array[nesw]);
                    if( (map.tiles[vx][vy].is == " "
                    ||  map.tiles[vx][vy].is == "H")
                    &&  map.tiles[vx][vy].visited == false){
                        console.log("parenting["+nesw+"]"+map.tiles[vx][vy].x+","+map.tiles[vx][vy].y+" to:"+x+","+y);
                        //set the route we took to get here
                        map.tiles[vx][vy].px = x;
                        map.tiles[vx][vy].py = y;
                        unfinished.push({"x":map.tiles[vx][vy].x, "y":map.tiles[vx][vy].y});
                    }
                }
                //visit this vertex
                map.tiles[x][y].visited = true;
            }

            console.log("END LOOP looking for path from:"+x+","+y+" to:"+ex+","+ey);
        }

        //walk back to start for our path
        var path = Array();
        if(x == ex && y == ey){
            while(x != sx && y != sy){
                path.push({"x":x,"y":y});
                console.log(x+","+y);
                x = map.tiles[x][y].px;
                y = map.tiles[x][y].py;
            }
            path.push({"x":x,"y":y});
            console.log("Path:"+util.inspect(path));
            return path;
        }
        return false;
    }
}

我做了一些樣本數據，它基本上有相同的問題，很難確定。 在下面的代碼中，“ me”是指Map（）對象。

function TestMap(){
    var me = this;
    this.paths = new Array();
    //width and height
    this.size = 10;
    this.num_tiles = this.size*this.size;
    //we can't build on the edge
    this.start = 1;
    this.end = this.size-this.start;

    //
    //
    //tiles
    ////////////////////////////////////////
    this.tiles = new Array();

    //
    //
    //print
    //////////////////////////////////////////
    this.print = function(){
        var mapscii = "";
        for(var y=this.end; y>-1; y--){
            for(var x=0; x<this.size; x++){

                    mapscii += this.tiles[x][y].is;

            }
            mapscii += "\n";
        }
        console.log(mapscii);
    }

    //
    //
    //setup the tile array and the associations
    /////////////////////////////////////////////////
    this.init_map = function (){
        for(var x=0; x<me.size; x++){
            me.tiles[x] = new Array();
            for(var y=0; y<me.size; y++){
                var t = new Tile(x, y);

                //draw bounds
                if(x==0 || y==0 || x==me.size-1 || y==me.size-1){
                    t.is = "#";
                }
                me.tiles[x][y] = t;
            }
        }
    }

    //
    //
    //setup the tile array and the associations
    /////////////////////////////////////////////////
    this.fake_map = function (){
        var fake_rooms = [      [2,2]
                            ,   [2,3]
                            ,   [3,2]
                            //, [3,3]

                            //, [5,2]
                            ,   [5,3]
                            ,   [6,2]
                            ,   [6,3]
                        ];

        var fake_doors = [
                                [3,3]
                            ,   [5,2]
                        ];

        for(var x=0; x<fake_rooms.length; x++){
            me.tiles[fake_rooms[x][0]][fake_rooms[x][1]].is = ".";
        }
        for(var x=0; x<fake_doors.length; x++){
            me.tiles[fake_doors[x][0]][fake_doors[x][1]].is = "H";
        }
    }

    this.fake_place_paths = function(){
        var bfs = new BFS();

        me.paths[0] = bfs.get_path(
                        3,3,
                        5,2,
                        me
            );
    }

    this.mark_paths = function(){
        for(var i=0; i<me.paths.length; i++){
            console.log(me.paths);
            var thispath = me.paths[i];
            console.log("["+i+"]"+thispath.x+","+thispath.y);
            me.tiles[thispath.x][thispath.y].is = "+";
        }
    }

    this.init_map();
    this.fake_map();
    this.fake_place_paths();
    this.print();
    this.mark_paths();
}

這就是“偽地圖”打印時的樣子。

＃=界限

。 =房間

H =門

##########
#        #
#        #
#        #
#        #
#        #
# .H ..  #
# .. H.  #
#        #
##########

這是我的調試輸出。

C:\Users\trans\Documents\JS>node test_bfs.js


looking for path from:3,3 to:5,2
[ [ 3, 4 ], [ 4, 3 ], [ 3, 2 ], [ 2, 3 ] ]
[ 3, 4 ]
parenting[0]3,4 to:3,3
[ 4, 3 ]
parenting[1]4,3 to:3,3
[ 3, 2 ]
[ 2, 3 ]
END LOOP looking for path from:3,3 to:5,2


looking for path from:3,4 to:5,2
[ [ 3, 5 ], [ 4, 4 ], [ 3, 3 ], [ 2, 4 ] ]
[ 3, 5 ]
parenting[0]3,5 to:3,4
[ 4, 4 ]
parenting[1]4,4 to:3,4
[ 3, 3 ]
[ 2, 4 ]
parenting[3]2,4 to:3,4
END LOOP looking for path from:3,4 to:5,2


looking for path from:4,3 to:5,2
[ [ 4, 4 ], [ 5, 3 ], [ 4, 2 ], [ 3, 3 ] ]
[ 4, 4 ]
parenting[0]4,4 to:4,3
[ 5, 3 ]
[ 4, 2 ]
parenting[2]4,2 to:4,3
[ 3, 3 ]
END LOOP looking for path from:4,3 to:5,2


looking for path from:3,5 to:5,2
[ [ 3, 6 ], [ 4, 5 ], [ 3, 4 ], [ 2, 5 ] ]
[ 3, 6 ]
parenting[0]3,6 to:3,5
[ 4, 5 ]
parenting[1]4,5 to:3,5
[ 3, 4 ]
[ 2, 5 ]
parenting[3]2,5 to:3,5
END LOOP looking for path from:3,5 to:5,2


looking for path from:4,4 to:5,2
[ [ 4, 5 ], [ 5, 4 ], [ 4, 3 ], [ 3, 4 ] ]
[ 4, 5 ]
parenting[0]4,5 to:4,4
[ 5, 4 ]
parenting[1]5,4 to:4,4
[ 4, 3 ]
[ 3, 4 ]
END LOOP looking for path from:4,4 to:5,2


looking for path from:2,4 to:5,2
[ [ 2, 5 ], [ 3, 4 ], [ 2, 3 ], [ 1, 4 ] ]
[ 2, 5 ]
parenting[0]2,5 to:2,4
[ 3, 4 ]
[ 2, 3 ]
[ 1, 4 ]
parenting[3]1,4 to:2,4
END LOOP looking for path from:2,4 to:5,2
END LOOP looking for path from:4,4 to:5,2


looking for path from:4,2 to:5,2
[ [ 4, 3 ], [ 5, 2 ], [ 4, 1 ], [ 3, 2 ] ]
[ 4, 3 ]
[ 5, 2 ]
parenting[1]5,2 to:4,2
[ 4, 1 ]
parenting[2]4,1 to:4,2
[ 3, 2 ]
END LOOP looking for path from:4,2 to:5,2
##########
#        #
#        #
#        #
#        #
#        #
# .H ..  #
# .. H.  #
#        #
##########

[ false ]
[0]undefined,undefined
C:\Users\trans\Documents\JS\testmap.js:102
                        me.tiles[thispath.x][thispath.y].is = "+";
                                            ^

TypeError: Cannot read property 'undefined' of undefined
    at TestMap.mark_paths (C:\Users\trans\Documents\JS\testmap.js:102:24)
    at new TestMap (C:\Users\trans\Documents\JS\testmap.js:110:7)
    at Object.<anonymous> (C:\Users\trans\Documents\JS\test_bfs.js:2:11)
    at Module._compile (module.js:570:32)
    at Object.Module._extensions..js (module.js:579:10)
    at Module.load (module.js:487:32)
    at tryModuleLoad (module.js:446:12)
    at Function.Module._load (module.js:438:3)
    at Module.runMain (module.js:604:10)
    at run (bootstrap_node.js:390:7)

Answer 1

主要問題是我離開循環的條件以及在獲取數據之前修改用於引用某些內容的變量。

           .......................

    //walk until we can't or we reach our destination
    while(unfinished.length){

        var new_location = unfinished.shift();

        x = new_location.x;
        y = new_location.y;

        if(x == ex && y == ey){
            unfinished.length = 0;
            continue;
        }

    ..........................

    //walk back to start for our path
    var path = Array();
    if(x == ex && y == ey){
        console.log("here");
        while(!(x == sx && y == sy)){
            path.push({"x":x,"y":y});
            console.log(x+","+y);
            //temporary to not screw up reference
            var tempx = map.tiles[x][y].px;
            tempx = map.tiles[x][y].px;
            y = map.tiles[x][y].py;
            x = tempx;
            console.log(x+","+y);
        }
        path.push({"x":x,"y":y});
        return path;
    }
    return false;