feat: add the solution of Flood Fill(733) with Java.

Author: Mukyu

README.md

@@ -83,7 +83,7 @@
 | [720][720-question] | [Longest Word in Dictionary][720-tips]                       | [✅][720-java] | [✅][720-js] |                  |
 | [724][724-question] | [Find Pivot Index][724-tips]                                 | [✅][724-java] | [✅][724-js] |                  |
 | [728][728-question] | [Self Dividing Numbers][728-tips]                            | [✅][728-java] | [✅][728-js] |                  |
-| [733][733-question] | [Flood Fill][733-tips]                                       |                | [✅][733-js] |                  |
+| [733][733-question] | [Flood Fill][733-tips]                                       | [✅][733-java] | [✅][733-js] |                  |
 | [744][744-question] | [Find Smallest Letter Greater Than Target][744-tips]         |                | [✅][744-js] |                  |
 | [746][746-question] | [Min Cost Climbing Stairs][746-tips]                         |                | [✅][746-js] |                  |
 | [747][747-question] | [Largest Number At Least Twice of Others][747-tips]          |                | [✅][747-js] |                  |
@@ -481,6 +481,7 @@
 [720-java]: ./src/_720/Solution.java
 [724-java]: ./src/_724/Solution.java
 [728-java]: ./src/_728/Solution.java
+[733-java]: ./src/_733/Solution.java
 [771-java]: ./src/_771/Solution.java
 [804-java]: ./src/_804/Solution.java
 

src/_733/Solution.java

@@ -0,0 +1,33 @@
+package _733;
+
+class Solution {
+    public int[][] floodFill(int[][] image, int sr, int sc, int newColor) {
+        int oldColor = image[sr][sc];
+        if (oldColor == newColor) {
+            return image;
+        }
+        dfs(image, sr, sc, oldColor, newColor);
+        return image;
+    }
+
+    private void dfs(int[][] image, int sr, int sc, int oldColor, int newColor) {
+        if (image[sr][sc] == oldColor) {
+            image[sr][sc] = newColor;
+            if (sr > 0) dfs(image, sr - 1, sc, oldColor, newColor);
+            if (sr + 1 < image.length) dfs(image, sr + 1, sc, oldColor, newColor);
+            if (sc > 0) dfs(image, sr, sc - 1, oldColor, newColor);
+            if (sc + 1 < image[sr].length) dfs(image, sr, sc + 1, oldColor, newColor);
+        }
+    }
+
+    public static void main(String[] args) {
+        Solution solution = new Solution();
+        int[][] image = solution.floodFill(new int[][]{{1, 1, 1}, {1, 1, 0}, {1, 0, 1}}, 1, 1, 2);
+        for (int[] row : image) {
+            for (int num : row) {
+                System.out.print(num + " ");
+            }
+            System.out.println();
+        }
+    }
+}

tips/733/README.md

@@ -1,46 +1,71 @@
-[xxxx][title]
+[Flood Fill ][title]
 
 ## Description
-// 抄题目
 
+An `image` is represented by a 2-D array of integers, each integer representing the pixel value of the image (from 0 to 65535).
 
-**Example:**
+Given a coordinate `(sr, sc)` representing the starting pixel (row and column) of the flood fill, and a pixel value `newColor`, "flood fill" the image.
+
+To perform a "flood fill", consider the starting pixel, plus any pixels connected 4-directionally to the starting pixel of the same color as the starting pixel, plus any pixels connected 4-directionally to those pixels (also with the same color as the starting pixel), and so on. Replace the color of all of the aforementioned pixels with the newColor.
+
+At the end, return the modified image.
+
+**Example 1:**
 
 ```
-// 抄Example
+Input: 
+image = [[1,1,1],[1,1,0],[1,0,1]]
+sr = 1, sc = 1, newColor = 2
+Output: [[2,2,2],[2,2,0],[2,0,1]]
+Explanation: 
+From the center of the image (with position (sr, sc) = (1, 1)), all pixels connected 
+by a path of the same color as the starting pixel are colored with the new color.
+Note the bottom corner is not colored 2, because it is not 4-directionally connected
+to the starting pixel.
 ```
 
 **Note:**
-// Note
 
-**Tags:** // tags
+The length of `image` and `image[0]` will be in the range `[1, 50]`.
 
+The given starting pixel will satisfy `0 <= sr < image.length` and `0 <= sc < image[0].length`.
 
-## 思路 1
-// 贴一些关键代码,说一些解题思路
-// (同一种语言可以写多种思路，与某种语言思路相同的另一种语言的思路无须赘述，但可以把代码贴在后面) 
-```java
+The value of each color in `image[i][j]` and `newColor` will be an integer in `[0, 65535]`.
 
-```
-```javascript
+**Tags:** [Depth-first Search](https://leetcode.com/tag/depth-first-search/)
 
-```
+## 思路
 
-## 思路 2
-// 贴一些关键代码,说一些解题思路
-```java
-
-```
+题目给出一个二维数组来表示一张图像，数组里的值对应每个像素的值。指定一个目标像素，要求将所有和此像素连通（连通方向为上下左右四个方向）或间接连通的像素都更改为新的像素值`newColor`。
 
-## 思路 3
-// 贴一些关键代码,说一些解题思路
-```kotlin
+简单的通过深度优先遍历将所有连通的像素改变即可。
 
+```java
+class Solution {
+    public int[][] floodFill(int[][] image, int sr, int sc, int newColor) {
+        int oldColor = image[sr][sc];
+        if (oldColor == newColor) {
+            return image;
+        }
+        dfs(image, sr, sc, oldColor, newColor);
+        return image;
+    }
+
+    private void dfs(int[][] image, int sr, int sc, int oldColor, int newColor) {
+        if (image[sr][sc] == oldColor) {
+            image[sr][sc] = newColor;
+            if (sr > 0) dfs(image, sr - 1, sc, oldColor, newColor);
+            if (sr + 1 < image.length) dfs(image, sr + 1, sc, oldColor, newColor);
+            if (sc > 0) dfs(image, sr, sc - 1, oldColor, newColor);
+            if (sc + 1 < image[sr].length) dfs(image, sr, sc + 1, oldColor, newColor);
+        }
+    }
+}
 ```
 
 ## 结语
-   
+
 如果你同我们一样热爱数据结构、算法、LeetCode，可以关注我们 GitHub 上的 LeetCode 题解：[LeetCode-Solution][ls]
 
-[title]: https://leetcode.com/problems/xxxx
+[title]: https://leetcode.com/problems/flood-fill/description/
 [ls]: https://github.com/RichCodersAndMe/LeetCode-Solution