Add solution #661

Author: JoshCrozier

README.md

@@ -497,6 +497,7 @@
 657|[Robot Return to Origin](./0657-robot-return-to-origin.js)|Easy|
 658|[Find K Closest Elements](./0658-find-k-closest-elements.js)|Medium|
 659|[Split Array into Consecutive Subsequences](./0659-split-array-into-consecutive-subsequences.js)|Medium|
+661|[Image Smoother](./0661-image-smoother.js)|Easy|
 680|[Valid Palindrome II](./0680-valid-palindrome-ii.js)|Easy|
 684|[Redundant Connection](./0684-redundant-connection.js)|Medium|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|

solutions/0661-image-smoother.js

@@ -0,0 +1,44 @@
+/**
+ * 661. Image Smoother
+ * https://leetcode.com/problems/image-smoother/
+ * Difficulty: Easy
+ *
+ * An image smoother is a filter of the size 3 x 3 that can be applied to each cell of an image by
+ * rounding down the average of the cell and the eight surrounding cells (i.e., the average of the
+ * nine cells in the blue smoother). If one or more of the surrounding cells of a cell is not
+ * present, we do not consider it in the average (i.e., the average of the four cells in the red
+ * smoother).
+ *
+ * Given an m x n integer matrix img representing the grayscale of an image, return the image after
+ * applying the smoother on each cell of it.
+ */
+
+/**
+ * @param {number[][]} img
+ * @return {number[][]}
+ */
+var imageSmoother = function(img) {
+  const result = new Array(img.length).fill().map(() => {
+    return new Array(img[0].length).fill(0);
+  });
+
+  for (let i = 0; i < img.length; i++) {
+    for (let j = 0; j < img[0].length; j++) {
+      let sum = 0;
+      let count = 0;
+      for (let di = -1; di <= 1; di++) {
+        for (let dj = -1; dj <= 1; dj++) {
+          const ni = i + di;
+          const nj = j + dj;
+          if (ni >= 0 && ni < img.length && nj >= 0 && nj < img[0].length) {
+            sum += img[ni][nj];
+            count++;
+          }
+        }
+      }
+      result[i][j] = Math.floor(sum / count);
+    }
+  }
+
+  return result;
+};