|
| 1 | +function orangesRotting(grid) { |
| 2 | + const rows = grid.length; |
| 3 | + const cols = grid[0].length; |
| 4 | + let queue = []; |
| 5 | + let freshOranges = 0; |
| 6 | + |
| 7 | + // Initialize the queue with all rotten oranges and count fresh oranges |
| 8 | + for (let r = 0; r < rows; r++) { |
| 9 | + for (let c = 0; c < cols; c++) { |
| 10 | + if (grid[r][c] === 2) { |
| 11 | + queue.push([r, c]); |
| 12 | + } else if (grid[r][c] === 1) { |
| 13 | + freshOranges++; |
| 14 | + } |
| 15 | + } |
| 16 | + } |
| 17 | + |
| 18 | + // If there are no fresh oranges, return 0 |
| 19 | + if (freshOranges === 0) return 0; |
| 20 | + |
| 21 | + let minutes = 0; |
| 22 | + const directions = [ |
| 23 | + [0, 1], // right |
| 24 | + [1, 0], // down |
| 25 | + [0, -1], // left |
| 26 | + [-1, 0] // up |
| 27 | + ]; |
| 28 | + |
| 29 | + // Step 2: Perform BFS |
| 30 | + while (queue.length > 0) { |
| 31 | + let size = queue.length; |
| 32 | + let newRotten = false; |
| 33 | + |
| 34 | + for (let i = 0; i < size; i++) { |
| 35 | + let [x, y] = queue.shift(); |
| 36 | + |
| 37 | + for (let [dx, dy] of directions) { |
| 38 | + let nx = x + dx; |
| 39 | + let ny = y + dy; |
| 40 | + |
| 41 | + // Check if the neighboring cell is a fresh orange |
| 42 | + if (nx >= 0 && ny >= 0 && nx < rows && ny < cols && grid[nx][ny] === 1) { |
| 43 | + grid[nx][ny] = 2; // Make it rotten |
| 44 | + freshOranges--; // Decrease count of fresh oranges |
| 45 | + queue.push([nx, ny]); // Add it to the queue |
| 46 | + newRotten = true; |
| 47 | + } |
| 48 | + } |
| 49 | + } |
| 50 | + |
| 51 | + // If rotten oranges exist, increment minutes |
| 52 | + if (newRotten) minutes++; |
| 53 | + } |
| 54 | + |
| 55 | + // Check if there are any fresh oranges left |
| 56 | + return freshOranges === 0 ? minutes : -1; |
| 57 | +} |
0 commit comments