refactor 407

Author: fishercoder1534

src/main/java/com/fishercoder/solutions/_407.java

@@ -27,63 +27,65 @@
 
  */
 public class _407 {
-    /**Reference: https://discuss.leetcode.com/topic/60418/java-solution-using-priorityqueue*/
-    public class Cell {
-        int row;
-        int col;
-        int height;
-
-        public Cell(int row, int col, int height) {
-            this.row = row;
-            this.col = col;
-            this.height = height;
+    public static class Solution1 {
+        /** Reference: https://discuss.leetcode.com/topic/60418/java-solution-using-priorityqueue */
+        public class Cell {
+            int row;
+            int col;
+            int height;
+
+            public Cell(int row, int col, int height) {
+                this.row = row;
+                this.col = col;
+                this.height = height;
+            }
         }
-    }
 
-    public int trapRainWater(int[][] heights) {
-        if (heights == null || heights.length == 0 || heights[0].length == 0) {
-            return 0;
-        }
+        public int trapRainWater(int[][] heights) {
+            if (heights == null || heights.length == 0 || heights[0].length == 0) {
+                return 0;
+            }
 
-        PriorityQueue<Cell> queue = new PriorityQueue<>(1, (a, b) -> a.height - b.height);
+            PriorityQueue<Cell> queue = new PriorityQueue<>(1, (a, b) -> a.height - b.height);
 
-        int m = heights.length;
-        int n = heights[0].length;
-        boolean[][] visited = new boolean[m][n];
+            int m = heights.length;
+            int n = heights[0].length;
+            boolean[][] visited = new boolean[m][n];
 
-        // Initially, add all the Cells which are on borders to the queue.
-        for (int i = 0; i < m; i++) {
-            visited[i][0] = true;
-            visited[i][n - 1] = true;
-            queue.offer(new Cell(i, 0, heights[i][0]));
-            queue.offer(new Cell(i, n - 1, heights[i][n - 1]));
-        }
+            // Initially, add all the Cells which are on borders to the queue.
+            for (int i = 0; i < m; i++) {
+                visited[i][0] = true;
+                visited[i][n - 1] = true;
+                queue.offer(new Cell(i, 0, heights[i][0]));
+                queue.offer(new Cell(i, n - 1, heights[i][n - 1]));
+            }
 
-        for (int i = 0; i < n; i++) {
-            visited[0][i] = true;
-            visited[m - 1][i] = true;
-            queue.offer(new Cell(0, i, heights[0][i]));
-            queue.offer(new Cell(m - 1, i, heights[m - 1][i]));
-        }
+            for (int i = 0; i < n; i++) {
+                visited[0][i] = true;
+                visited[m - 1][i] = true;
+                queue.offer(new Cell(0, i, heights[0][i]));
+                queue.offer(new Cell(m - 1, i, heights[m - 1][i]));
+            }
 
-        // from the borders, pick the shortest cell visited and check its neighbors:
-        // if the neighbor is shorter, collect the water it can trap and update its height as its height plus the water trapped
-        // add all its neighbors to the queue.
-        int[][] dirs = new int[][]{{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
-        int res = 0;
-        while (!queue.isEmpty()) {
-            Cell cell = queue.poll();
-            for (int[] dir : dirs) {
-                int row = cell.row + dir[0];
-                int col = cell.col + dir[1];
-                if (row >= 0 && row < m && col >= 0 && col < n && !visited[row][col]) {
-                    visited[row][col] = true;
-                    res += Math.max(0, cell.height - heights[row][col]);
-                    queue.offer(new Cell(row, col, Math.max(heights[row][col], cell.height)));
+            // from the borders, pick the shortest cell visited and check its neighbors:
+            // if the neighbor is shorter, collect the water it can trap and update its height as its height plus the water trapped
+            // add all its neighbors to the queue.
+            int[][] dirs = new int[][] {{-1, 0}, {1, 0}, {0, -1}, {0, 1}};
+            int res = 0;
+            while (!queue.isEmpty()) {
+                Cell cell = queue.poll();
+                for (int[] dir : dirs) {
+                    int row = cell.row + dir[0];
+                    int col = cell.col + dir[1];
+                    if (row >= 0 && row < m && col >= 0 && col < n && !visited[row][col]) {
+                        visited[row][col] = true;
+                        res += Math.max(0, cell.height - heights[row][col]);
+                        queue.offer(new Cell(row, col, Math.max(heights[row][col], cell.height)));
+                    }
                 }
             }
-        }
 
-        return res;
+            return res;
+        }
     }
 }