added js solution 994

Author: sambabib

javascript/_994.js

@@ -0,0 +1,57 @@
+function orangesRotting(grid) {
+  const rows = grid.length;
+  const cols = grid[0].length;
+  let queue = [];
+  let freshOranges = 0;
+
+  // Initialize the queue with all rotten oranges and count fresh oranges
+  for (let r = 0; r < rows; r++) {
+      for (let c = 0; c < cols; c++) {
+          if (grid[r][c] === 2) {
+              queue.push([r, c]);
+          } else if (grid[r][c] === 1) {
+              freshOranges++;
+          }
+      }
+  }
+
+  // If there are no fresh oranges, return 0
+  if (freshOranges === 0) return 0;
+
+  let minutes = 0;
+  const directions = [
+      [0, 1], // right
+      [1, 0], // down
+      [0, -1], // left
+      [-1, 0] // up
+  ];
+
+  // Step 2: Perform BFS
+  while (queue.length > 0) {
+      let size = queue.length;
+      let newRotten = false;
+
+      for (let i = 0; i < size; i++) {
+          let [x, y] = queue.shift();
+
+          for (let [dx, dy] of directions) {
+              let nx = x + dx;
+              let ny = y + dy;
+
+              // Check if the neighboring cell is a fresh orange
+              if (nx >= 0 && ny >= 0 && nx < rows && ny < cols && grid[nx][ny] === 1) {
+                  grid[nx][ny] = 2; // Make it rotten
+                  freshOranges--; // Decrease count of fresh oranges
+                  queue.push([nx, ny]); // Add it to the queue
+                  newRotten = true;
+              }
+          }
+      }
+
+      // If rotten oranges exist, increment minutes
+      if (newRotten) minutes++;
+  }
+
+ // Check if there are any fresh oranges left
+  return freshOranges === 0 ? minutes : -1;
+}