* https://leetcode.com/problems/walls-and-gates/
* Time O(ROWS * COLS) | Space O(ROWS * COLS)
* @param {number[][]} rooms
* @return {void} Do not return anything, modify rooms in-place instead.
*/
var wallsAndGates = function (rooms) {
const [rows, cols] = [rooms.length, rooms[0].length];
for (let row = 0; row < rows; row++) {
for (let col = 0; col < cols; col++) {
const isGate = rooms[row][col] === 0;
if (!isGate) continue;
dfs(rooms, row, col);
}
}
};
const dfs = (rooms, row, col) => {
const [rows, cols] = [rooms.length, rooms[0].length];
for (const [_row, _col] of getNeighbors(row, rows, col, cols)) {
const isPreviousDistanceGreater =
rooms[_row][_col] <= rooms[row][col] + 1;
if (isPreviousDistanceGreater) continue;
rooms[_row][_col] = rooms[row][col] + 1;
dfs(rooms, _row, _col);
}
};
var getNeighbors = (row, rows, col, cols) =>
[
[0, 1],
[0, -1],
[1, 0],
[-1, 0],
]
.map(([_row, _col]) => [row + _row, col + _col])
.filter(
([_row, _col]) =>
0 <= _row && 0 <= _col && _row < rows && _col < cols,
);
* https://leetcode.com/problems/walls-and-gates/
* Time O(ROWS * COLS) | Space O(ROWS * COLS)
* @param {number[][]} rooms
* @return {void} Do not return anything, modify rooms in-place instead.
*/
var wallsAndGates = function (rooms) {
const queue = searchGrid(rooms);
bfs(rooms, queue);
};
const searchGrid = (rooms, queue = new Queue([])) => {
const [rows, cols] = [rooms.length, rooms[0].length];
for (let row = 0; row < rows; row++) {
for (let col = 0; col < cols; col++) {
const isGate = rooms[row][col] === 0;
if (!isGate) continue;
queue.enqueue([row, col]);
}
}
return queue;
};
const bfs = (rooms, queue) => {
while (!queue.isEmpty()) {
for (let i = queue.size() - 1; 0 <= i; i--) {
checkNeighbors(rooms, queue);
}
}
};
const checkNeighbors = (rooms, queue) => {
const [rows, cols] = [rooms.length, rooms[0].length];
const [row, col] = queue.dequeue();
for (const [_row, _col] of getNeighbors(row, rows, col, cols)) {
const isINF = rooms[_row][_col] === 2147483647;
if (!isINF) continue;
rooms[_row][_col] = rooms[row][col] + 1;
queue.enqueue([_row, _col]);
}
};
var getNeighbors = (row, rows, col, cols) =>
[
[0, 1],
[0, -1],
[1, 0],
[-1, 0],
]
.map(([_row, _col]) => [row + _row, col + _col])
.filter(
([_row, _col]) =>
0 <= _row && 0 <= _col && _row < rows && _col < cols,
);