"use strict";
function createMaze(mazeStr) {
var maze, lines, cell, row, ch, id, r, c, n, m;
maze = {
nodesRowCol: [],
nodes: [],
target: null,
marbles: []
};
id = 0;
lines = mazeStr.split("\n");
for (r = 0; r < lines.length; r++) {
maze.nodesRowCol[r] = row = [];
for (c = 0; c < lines[r].length; c++) {
ch = lines[r].charAt(c);
if (ch !== '#') {
maze.nodes[id] = row[c] = cell = {
row: r,
col: c,
id: id++,
comeFrom: [],
};
// Keep track of target and marbles
if (ch === '*') maze.target = cell;
if (ch === '.') maze.marbles.push(cell);
}
}
}
// Add neighbours
for (n = 0; n < maze.nodes.length; n++) {
cell = maze.nodes[n];
cell.neighbours = [
maze.nodesRowCol[cell.row-1][cell.col], /* north */
maze.nodesRowCol[cell.row][cell.col+1], /* east */
maze.nodesRowCol[cell.row+1][cell.col], /* south */
maze.nodesRowCol[cell.row][cell.col-1] /* west */
];
}
// Add marble moves in two steps
for (n = 0; n < maze.nodes.length; n++) {
cell = maze.nodes[n];
cell.moves = [
cell.neighbours[0] ? cell.neighbours[0].moves[0] : cell, /* north */
null,
null,
cell.neighbours[3] ? cell.neighbours[3].moves[3] : cell, /* west */
];
}
for (n = maze.nodes.length - 1; n >= 0; n--) {
cell = maze.nodes[n];
cell.moves[1] = cell.neighbours[1] ? cell.neighbours[1].moves[1] : cell; /* west */
cell.moves[2] = cell.neighbours[2] ? cell.neighbours[2].moves[2] : cell; /* south */
}
// add reverse-move ("marble can come from") data
for (n = maze.nodes.length - 1; n >= 0; n--) {
cell = maze.nodes[n];
for (m = 0; m < 4; m++) {
if (cell.moves[m] !== cell) cell.moves[m].comeFrom.push(cell);
}
}
return maze;
}
function setDistances(maze) {
var n, cell, distance, stack, newStack, i;
// clear distance information
for (n = 0; n < maze.nodes.length; n++) {
maze.nodes[n].distance = Number.POSITIVE_INFINITY;
}
// set initial distance
cell = maze.target;
cell.distance = distance = 0;
// BSF loop to set the distance for each cell that can be reached
stack = cell.comeFrom.slice();
while (stack.length) {
distance++;
newStack = [];
for (i = 0; i < stack.length; i++) {
cell = stack[i];
if (distance < cell.distance) {
cell.distance = distance;
newStack = newStack.concat(cell.comeFrom);
}
}
stack = newStack;
}
}
function evaluatedPosition(position, visited) {
// Assign heurstic cost to position
var m, ids;
position.cost = 0;
ids = []; // keep track of marble positions
for (m = 0; m < position.marbles.length; m++) {
// If mulitple marbles are at same cell, only account for that cell once.
// This will favour such positions:
if (ids[position.marbles[m].id] === undefined) {
// Make higher distances cost a lot, so that insentive
// is to improve the position of the worst placed marble
position.cost += Math.pow(position.marbles[m].distance, 2);
ids[position.marbles[m].id] = position.marbles[m].id;
}
}
// Assign some unique string, identifying the marble configuration
position.id = ids.join(',');
// If position was already visited before, give it the maximum cost
if (visited[position.id]) position.cost = Number.POSITIVE_INFINITY;
// Mark position as visited
visited[position.id] = 1;
return position;
}
function createMove(dir, marbles, visited) {
var m, movedMarbles;
movedMarbles = [];
for (m = 0; m < marbles.length; m++) {
movedMarbles[m] = marbles[m].moves[dir];
}
return evaluatedPosition({
dir: dir,
marbles: movedMarbles,
}, visited);
}
function solve(maze) {
var visited = {}; // nothing visited yet
function recurse (position) {
var ids, m, moves, i, path;
if (position.cost == 0) return []; // marbles are all on target spot.
if (!isFinite(position.cost)) return false; // no solution
// get move list
moves = [];
for (i = 0; i < 4; i++) {
moves[i] = createMove(i, position.marbles, visited);
}
// apply heuristic: sort the 4 moves by ascending cost
moves.sort(function (a,b) { return a.cost - b.cost });
for (i = 0; i < 4; i++) {
//console.log('=== move === ' + moves[i].dir);
path = recurse(moves[i]);
if (path !== false) return [moves[i].dir].concat(path);
}
return false; // no solution found
}
// Enrich initial position with cost, and start recursive search
return recurse(evaluatedPosition({
marbles: maze.marbles
}, visited));
}
// # = wall
// * = target
// . = marble
var mazeStr = `
###########
# # #*#
# # #.# .#
# #. #.# #
# # # ### #
# # #
###########
`.trim();
var maze = createMaze(mazeStr);
setDistances(maze);
console.log('#=wall, .=marble, *=target\n\n' + mazeStr);
var moves = solve(maze);
console.log('moves (0=north,1=east,2=south,3=west): ' + moves);
「ボールは衝突できません」とは、他の前提の一部に矛盾しているようです。 – m69
あなたは正しいです、それは私の言葉の貧しい言葉です。私は彼らがお互いをブロックすることはできないと言っていた（あるいは、衝突することのできないすべてのゴーストボール）。私はそれを編集します！ – Eric