add 1030

Author: fishercoder1534

README.md

@@ -27,6 +27,7 @@ Your ideas/fixes/algorithms are more than welcome!
 
 |  #  |      Title     |   Solutions   | Time          | Space         | Video  | Difficulty  | Tag                   
 |-----|----------------|---------------|---------------|---------------|--------|-------------|-------------
+|1030|[Matrix Cells in Distance Order](https://leetcode.com/problems/matrix-cells-in-distance-order/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1030.java) | O(R*C) | O(1) | |Easy|
 |1022|[Sum of Root To Leaf Binary Numbers](https://leetcode.com/problems/sum-of-root-to-leaf-binary-numbers/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1022.java) | O(n) | O(n) | |Easy|
 |1021|[Remove Outermost Parentheses](https://leetcode.com/problems/remove-outermost-parentheses/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1021.java) | O(n) | O(n) | |Easy|
 |1020|[Number of Enclaves](https://leetcode.com/problems/number-of-enclaves/)|[Solution](../master/src/main/java/com/fishercoder/solutions/_1020.java) | O(mn) | O(mn) | |Medium|Graph, DFS, BFS, recursion|

src/main/java/com/fishercoder/solutions/_1030.java

@@ -0,0 +1,69 @@
+package com.fishercoder.solutions;
+
+import java.util.ArrayList;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.Queue;
+
+/**
+ * 1030. Matrix Cells in Distance Order
+ *
+ * We are given a matrix with R rows and C columns has cells with integer coordinates (r, c), where 0 <= r < R and 0 <= c < C.
+ *
+ * Additionally, we are given a cell in that matrix with coordinates (r0, c0).
+ *
+ * Return the coordinates of all cells in the matrix, sorted by their distance from (r0, c0) from smallest distance to largest distance.  Here, the distance between two cells (r1, c1) and (r2, c2) is the Manhattan distance, |r1 - r2| + |c1 - c2|.  (You may return the answer in any order that satisfies this condition.)
+ *
+ * Example 1:
+ * Input: R = 1, C = 2, r0 = 0, c0 = 0
+ * Output: [[0,0],[0,1]]
+ * Explanation: The distances from (r0, c0) to other cells are: [0,1]
+ *
+ * Example 2:
+ * Input: R = 2, C = 2, r0 = 0, c0 = 1
+ * Output: [[0,1],[0,0],[1,1],[1,0]]
+ * Explanation: The distances from (r0, c0) to other cells are: [0,1,1,2]
+ * The answer [[0,1],[1,1],[0,0],[1,0]] would also be accepted as correct.
+ *
+ * Example 3:
+ * Input: R = 2, C = 3, r0 = 1, c0 = 2
+ * Output: [[1,2],[0,2],[1,1],[0,1],[1,0],[0,0]]
+ * Explanation: The distances from (r0, c0) to other cells are: [0,1,1,2,2,3]
+ * There are other answers that would also be accepted as correct, such as [[1,2],[1,1],[0,2],[1,0],[0,1],[0,0]].
+ *
+ * Note:
+ *
+ * 1 <= R <= 100
+ * 1 <= C <= 100
+ * 0 <= r0 < R
+ * 0 <= c0 < C
+ * */
+public class _1030 {
+    public static class Solution1 {
+        public int[][] allCellsDistOrder(int R, int C, int r0, int c0) {
+            int[][] result = new int[R * C][2];
+            Queue<int[]> queue = new LinkedList<>();
+            queue.offer(new int[]{r0, c0});
+            boolean[][] visited = new boolean[R][C];
+            int i = 0;
+            while (!queue.isEmpty()) {
+                int[] cell = queue.poll();
+                int row = cell[0];
+                int col = cell[1];
+
+                if (row < 0 || row >= R || col < 0 || col >= C || visited[row][col]) {
+                    continue;
+                }
+
+                visited[row][col] = true;
+                result[i++] = new int[]{row, col};
+                queue.offer(new int[]{row, col + 1});
+                queue.offer(new int[]{row + 1, col});
+                queue.offer(new int[]{row - 1, col});
+                queue.offer(new int[]{row, col - 1});
+
+            }
+            return result;
+        }
+    }
+}

src/test/java/com/fishercoder/_1030Test.java

@@ -0,0 +1,31 @@
+package com.fishercoder;
+
+import com.fishercoder.common.utils.CommonUtils;
+import com.fishercoder.solutions._1030;
+import org.junit.BeforeClass;
+import org.junit.Test;
+
+public class _1030Test {
+    private static _1030.Solution1 solution1;
+
+    @BeforeClass
+    public static void setup() {
+        solution1 = new _1030.Solution1();
+    }
+
+    @Test
+    public void test1() {
+        CommonUtils.print2DIntArray(solution1.allCellsDistOrder(1, 2, 0, 0));
+    }
+
+    @Test
+    public void test2() {
+        CommonUtils.print2DIntArray(solution1.allCellsDistOrder(2, 2, 0, 1));
+    }
+
+    @Test
+    public void test3() {
+        CommonUtils.print2DIntArray(solution1.allCellsDistOrder(2, 3, 1, 2));
+    }
+
+}