MAP=`
##########
# a b@ c #
##########
`.split('\n').slice(1,-1)
DIRS = [
[0, 1], // right
[1, 0], // down
[-1, 0], // left
[0, -1], // up
];
function move([i, j], [di, dj]) {
return [i + di, j + dj];
}
on = ([i, j], [i2, j2]) => i == i2 && j == j2
function findItems(origin) {
let visited = {};
let queue = [[origin, null]];
let items = [];
const isOrigin = (p) => on(p, origin);
const char = ([i, j]) => MAP[i][j];
const isWall = (p) => char(p) == "#";
const isItem = (p) => char(p) >= "a" && char(p) <= "z";
function assemblePath(dest) {
let p = dest;
const res = [p];
while ((p = visited[p])) {
if (isOrigin(p)) break;
res.push(p);
}
return res.reverse();
}
while (queue.length) {
let [current, parent] = queue.shift();
visited[current] = parent;
if (isItem(current)) {
let path = assemblePath(current);
items.push([char(current), current, path.length])
}
for (let dir of DIRS) {
let next = move(current, dir);
if (isWall(next)) continue;
if (visited[next]) continue;
queue.push([next, current]);
}
}
return items;
}
findItems([1, 5])
function findObjectsW(origin) {
let visited = {};
let queue = [[origin, null]];
let objects = [];
const isOrigin = (p) => on(p, origin);
const char = ([i, j]) => MAP[i][j];
const isWall = (p) => char(p) == "#";
const isObject = (p) => char(p) >= "a" && char(p) <= "z";
function assemblePath(dest) {
let p = dest;
const res = [p];
while ((p = visited[p])) {
if (isOrigin(p)) break;
res.push(p);
}
return res.reverse();
}
while (queue.length) {
let [current, parent] = queue.shift();
visited[current] = parent;
if (isObject(current)) {
let path = assemblePath(current);
objects.push([char(current), current, path.length])
continue
}
for (let dir of DIRS) {
let next = move(current, dir);
if (isWall(next)) continue;
if (visited[next]) continue;
queue.push([next, current]);
}
}
return objects;
}
findObjectsW([1,5])
findObjectsW([1, 4])
function findItemsN(origin, collected) {
let visited = {};
let queue = [[origin, null]];
let items = [];
const isOrigin = (p) => on(p, origin);
const char = ([i, j]) => MAP[i][j];
const isWall = (p) => char(p) == "#";
const isItem = (p) => {
const c = char(p)
return c >= "a" && c <= "z" && !collected.includes(c)
}
function assemblePath(dest) {
let p = dest;
const res = [p];
while ((p = visited[p])) {
if (isOrigin(p)) break;
res.push(p);
}
return res.reverse();
}
while (queue.length) {
let [current, parent] = queue.shift();
visited[current] = parent;
if (isItem(current)) {
let path = assemblePath(current);
items.push([char(current), current, path.length])
continue
}
for (let dir of DIRS) {
let next = move(current, dir);
if (isWall(next)) continue;
if (visited[next]) continue;
queue.push([next, current]);
}
}
return items;
}
findItemsN([1, 4], 'b')
findItemsN([1, 2], 'ba')
findItemsN([1, 7], 'bac')
findItemsN([1, 5], '')
findItemsN([1, 7], 'c')
findItemsN([1, 4], 'cb')
findItemsN([1, 2], 'cba')
function findItemsM(map, origin, collected) {
let visited = {};
let queue = [[origin, null]];
let objects = [];
const isOrigin = (p) => on(p, origin);
const char = ([i, j]) => map[i][j];
const isWall = (p) => char(p) == "#";
const isItem = (p) => {
const c = char(p)
return c >= "a" && c <= "z" && !collected.includes(c)
}
function assemblePath(dest) {
let p = dest;
const res = [p];
while ((p = visited[p])) {
if (isOrigin(p)) break;
res.push(p);
}
return res.reverse();
}
while (queue.length) {
let [current, parent] = queue.shift();
visited[current] = parent;
if (isItem(current)) {
let path = assemblePath(current);
objects.push([char(current), current, path.length])
continue
}
for (let dir of DIRS) {
let next = move(current, dir);
if (isWall(next)) continue;
if (visited[next]) continue;
queue.push([next, current]);
}
}
return objects;
}
function findMinRoute(map, origin) {
let minCollected, minDist = Infinity
function visit(current, distance, collected) {
const items = findItemsM(map, current, collected)
if (items.length == 0) {
if (distance < minDist) {
minDist = distance
minCollected = collected
}
return
}
for (let [name, pos, steps] of items) {
visit(pos, distance + steps, collected + name)
}
}
visit(origin, 0, '')
return [minDist, minCollected]
}
findMinRoute(MAP, [1, 5])
MAP2 = `
##################
# a @ d #
### ##############
# e b c #
##################
`.split('\n').slice(1,-1)
findMinRoute(MAP2, [1, 5])
MAP3 = `
########################
# @a b d#
### # # ## ### ########
#h# # # ## ### ######e#
# #g#f## c# #
########################
`.split("\n")
.slice(1, -1);
findMinRoute(MAP3, [1, 5])
function findMinRouteR(map, origin) {
function minDistance(collected, current) {
const items = findItemsM(map, current, collected)
if (items.length == 0) return 0
let distances = []
for (let [item, itemPos, itemSteps] of items) {
distances.push(itemSteps + minDistance(collected + item, itemPos))
}
return Math.min(...distances)
}
return minDistance('', origin)
}
findMinRouteR(MAP, [1, 5])
findMinRouteR(MAP2, [1, 5])
findMinRouteR(MAP3, [1, 5])
function key(str) {
return str.slice(0, -1).split('').sort().join('') + str[str.length - 1]
}
function findMinRouteM(map, start) {
const m = {}
function minDistance(collected, current) {
const items = findItemsM(map, current, collected)
if (items.length == 0) return 0
const k = key(collected)
if (k in m) return m[k]
let distances = []
for (let [item, itemPos, itemDist] of items) {
distances.push(itemDist +
minDistance(collected + item, itemPos)
)
}
m[k] = Math.min(...distances)
return m[k]
}
return minDistance('', start)
}
findMinRouteM(MAP, [1, 5])
findMinRouteM(MAP2, [1, 5])
findMinRouteM(MAP3, [1, 5])
MAP4 = `
#################
#i. ..c...e.. .p#
########.########
#j. ..b...f.. .o#
########@########
#k. ..a...g.. .n#
########.########
#l. ..d...h.. .m#
#################
`.split('\n').slice(1,-1)
findMinRouteM(MAP4, [4, 8])
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.