ImageSmoother661

Author: fluency03

README.md

@@ -44,11 +44,11 @@
 | [Graph](https://github.com/fluency03/leetcode-java/blob/master/src/graph) |
 
 
-# Total: 294
+# Total: 295
 
 | Easy |  Medium | Hard | - |
 |:----:|:-------:|:----:|:-:|
-|  77  |   162   |  52  | 3 |
+|  78  |   162   |  52  | 3 |
 
 
 | Question | Solution | Difficulty |
@@ -324,6 +324,7 @@
 | [657. Judge Route Circle](https://leetcode.com/problems/judge-route-circle/) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/JudgeRouteCircle657.java) | Easy |
 | [658. Find K Closest Elements](https://leetcode.com/problems/find-k-closest-elements//) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/FindKClosestElements658.java) | Medium |
 | [659. Split Array into Consecutive Subsequences](https://leetcode.com/problems/split-array-into-consecutive-subsequences/) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/SplitArrayIntoConsecutiveSubsequences659.java) | Medium |
+| [661. Image Smoother](https://leetcode.com/problems/image-smoother/) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/ImageSmoother661.java) | Easy |
 | [671. Second Minimum Node In a Binary Tree](https://leetcode.com/problems/second-minimum-node-in-a-binary-tree/) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/SecondMinimumNodeInABinaryTree671.java) | Easy |
 | [674. Longest Continuous Increasing Subsequence](https://leetcode.com/problems/longest-continuous-increasing-subsequence/) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/LongestContinuousIncreasingSubsequence674.java) | Easy |
 | [680. Valid Palindrome II](https://leetcode.com/problems/valid-palindrome-ii/) | [Solution](https://github.com/fluency03/leetcode-java/blob/master/src/ValidPalindromeII680.java) | Easy |

src/ImageSmoother661.java

@@ -0,0 +1,53 @@
+/**
+ * Given a 2D integer matrix M representing the gray scale of an image, you
+ * need to design a smoother to make the gray scale of each cell becomes the
+ * average gray scale (rounding down) of all the 8 surrounding cells and itself.
+ * If a cell has less than 8 surrounding cells, then use as many as you can.
+ * 
+ * Example 1:
+ * 
+ * Input:
+ * [[1,1,1],
+ *  [1,0,1],
+ *  [1,1,1]]
+ * 
+ * Output:
+ * [[0, 0, 0],
+ *  [0, 0, 0],
+ *  [0, 0, 0]]
+ * 
+ * Explanation:
+ * For the point (0,0), (0,2), (2,0), (2,2): floor(3/4) = floor(0.75) = 0
+ * For the point (0,1), (1,0), (1,2), (2,1): floor(5/6) = floor(0.83333333) = 0
+ * For the point (1,1): floor(8/9) = floor(0.88888889) = 0
+ * 
+ * Note:
+ * The value in the given matrix is in the range of [0, 255].
+ * The length and width of the given matrix are in the range of [1, 150].
+ */
+
+public class ImageSmoother661 {
+    private int[][] dirs = new int[][]{{0,0}, {0,1}, {1,1}, {1,0}, {1,-1}, {0,-1}, {-1,0}, {-1,-1}, {-1,1}};
+    public int[][] imageSmoother(int[][] M) {
+        int lenI = M.length;
+        int lenJ = M[0].length;
+        int[][] newScale = new int[lenI][lenJ];
+        
+        for (int i=0; i<lenI; i++) {
+            for (int j=0; j<lenJ; j++) {
+                int sum = 0;
+                int count = 0;
+                for (int[] dir: dirs) {
+                    int ii = i+dir[0];
+                    int jj = j+dir[1];
+                    if (ii >= 0 && jj >= 0 && ii < lenI && jj < lenJ) {
+                        sum += M[ii][jj];
+                        count++;
+                    }
+                }
+                newScale[i][j] = sum / count;
+            }
+        }
+        return newScale;
+    }
+}