feat(leetcode): #16, study the No0695 and No0733

leetcode/src/main/java/com/github/lucaseo90/easy/No0733.java

@@ -0,0 +1,54 @@
+package com.github.lucaseo90.easy;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class No0733 {
+    private final int[] dx = {1, -1, 0, 0};
+    private final int[] dy = {0, 0, 1, -1};
+
+    public int[][] floodFill(int[][] image, int sr, int sc, int newColor) {
+        int n = image.length;
+        int m = image[0].length;
+
+        boolean[][] visited = new boolean[n][];
+        for (int i = 0; i < n; i++) {
+            visited[i] = new boolean[m];
+        }
+
+        Queue<Point> queue = new LinkedList<>();
+        queue.add(new Point(sr, sc));
+
+        while (!queue.isEmpty()) {
+            Point point = queue.poll();
+            int x = point.x;
+            int y = point.y;
+
+            visited[x][y] = true;
+
+            for (int i = 0; i < dx.length; i++) {
+                int dx = x + this.dx[i];
+                int dy = y + this.dy[i];
+
+                if (dx >= 0 && dy >= 0 && dx < n && dy < m) {
+                    if (!visited[dx][dy] && image[x][y] == image[dx][dy]) {
+                        queue.add(new Point(dx, dy));
+                    }
+                }
+            }
+            image[x][y] = newColor;
+        }
+
+        return image;
+    }
+
+    private class Point {
+        private int x;
+        private int y;
+
+        public Point(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+}

leetcode/src/main/java/com/github/lucaseo90/medium/No0695.java

@@ -0,0 +1,73 @@
+package com.github.lucaseo90.medium;
+
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class No0695 {
+    private final int[] dx = {1, -1, 0, 0};
+    private final int[] dy = {0, 0, 1, -1};
+
+    public int maxAreaOfIsland(int[][] grid) {
+        int n = grid.length;
+        int m = grid[0].length;
+
+        boolean[][] visited = new boolean[n][];
+        for (int i = 0; i < n; i++) {
+            visited[i] = new boolean[m];
+        }
+
+        int largestIsland = 0;
+        for (int i = 0; i < n; i++) {
+            for (int j = 0; j < m; j++) {
+                if (grid[i][j] == 1 && !visited[i][j]) {
+                    int islandSize = this.traverseIsland(grid, visited, i, j, n, m);
+                    if (largestIsland < islandSize) {
+                        largestIsland = islandSize;
+                    }
+                }
+            }
+        }
+        return largestIsland;
+    }
+
+    private int traverseIsland(int[][] grid, boolean[][] visited, int startX, int startY, int n, int m) {
+        Queue<Point> queue = new LinkedList<>();
+        queue.add(new Point(startX, startY));
+
+        int size = 0;
+
+        size++;
+        visited[startX][startY] = true;
+
+        while (!queue.isEmpty()) {
+            Point point = queue.poll();
+            int x = point.x;
+            int y = point.y;
+
+            for (int i = 0; i < dx.length; i++) {
+                int dx = x + this.dx[i];
+                int dy = y + this.dy[i];
+
+                if (dx >= 0 && dy >= 0 && dx < n && dy < m) {
+                    if (!visited[dx][dy] && grid[dx][dy] == 1) {
+                        queue.add(new Point(dx, dy));
+                        visited[dx][dy] = true;
+                        size++;
+                    }
+                }
+            }
+        }
+
+        return size;
+    }
+
+    private class Point {
+        private int x;
+        private int y;
+
+        public Point(int x, int y) {
+            this.x = x;
+            this.y = y;
+        }
+    }
+}

leetcode/src/test/java/com/github/lucaseo90/easy/No0733Test.java

@@ -0,0 +1,28 @@
+package com.github.lucaseo90.easy;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.Arrays;
+
+public class No0733Test {
+
+    private No0733 no0733 = new No0733();
+
+    @Test
+    public void testExample01() {
+        Assert.assertEquals("[[2, 2, 2], [2, 2, 0], [2, 0, 1]]", (Arrays.deepToString(no0733.floodFill(new int[][]{
+                {1, 1, 1},
+                {1, 1, 0},
+                {1, 0, 1},
+        }, 1, 1, 2))));
+    }
+
+    @Test
+    public void testExample02() {
+        Assert.assertEquals("[[2, 2, 2], [2, 2, 2]]", (Arrays.deepToString(no0733.floodFill(new int[][]{
+                {0, 0, 0},
+                {0, 0, 0},
+        }, 0, 0, 2))));
+    }
+}

leetcode/src/test/java/com/github/lucaseo90/medium/No0695Test.java

@@ -0,0 +1,40 @@
+package com.github.lucaseo90.medium;
+
+import org.junit.Assert;
+import org.junit.Test;
+
+public class No0695Test {
+
+    private No0695 no0695 = new No0695();
+
+    @Test
+    public void testExample01() {
+        Assert.assertEquals(6, no0695.maxAreaOfIsland(new int[][]{
+                {0, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0},
+                {0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
+                {0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0},
+                {0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0},
+                {0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0},
+                {0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 0},
+                {0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0, 0},
+                {0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0}
+        }));
+    }
+
+    @Test
+    public void testExample02() {
+        Assert.assertEquals(0, no0695.maxAreaOfIsland(new int[][]{
+                {0, 0, 0, 0, 0, 0, 0, 0},
+        }));
+    }
+
+    @Test
+    public void wrongAnswerExample01() {
+        Assert.assertEquals(4, no0695.maxAreaOfIsland(new int[][]{
+                {1, 1, 0, 0, 0},
+                {1, 1, 0, 0, 0},
+                {0, 0, 0, 1, 1},
+                {0, 0, 0, 1, 1},
+        }));
+    }
+}