fd

Author: dingjikerbo

README.md

@@ -385,5 +385,7 @@
 |669|[Trim a Binary Search Tree](https://leetcode.com/problems/trim-a-binary-search-tree/)|[Java](leetcode/solution/src/TrimABinarySearchTree.java)|100||
 |681|[Next Closest Time](https://leetcode.com/problems/next-closest-time/)|[Java](leetcode/solution/src/NextClosestTime.java)|80|这题多做几遍|
 |684|[Redundant Connection](https://leetcode.com/problems/redundant-connection/)| [Java](leetcode/solution/src/RedundantConnection.java)|||
+|695|[Max Area of Island](https://leetcode.com/problems/max-area-of-island/)|[Java](leetcode/solution/src/MaxAreaOfIsland.java)|100||
 |771|[Jewels and Stones](https://leetcode.com/problems/jewels-and-stones/)|[Java](leetcode/solution/src/JewelsAndStones.java)|100||
-|904|[Fruit Into Baskets](https://leetcode.com/problems/fruit-into-baskets/)|[Java](leetcode/solution/src/FruitIntoBaskets.java)|90||
+|904|[Fruit Into Baskets](https://leetcode.com/problems/fruit-into-baskets/)|[Java](leetcode/solution/src/FruitIntoBaskets.java)|90||
+|929|[Unique Email Addresses](https://leetcode.com/problems/unique-email-addresses/)|[Java](leetcode/solution/src/UniqueEmailAddresses.java)|90||

leetcode/solution/src/GroupAnagrams.java

@@ -5,6 +5,7 @@
 
 public class GroupAnagrams {
 
+    // 12ms
     public List<List<String>> groupAnagrams(String[] strs) {
         HashMap<String, List<String>> map = new HashMap<>();
 

leetcode/solution/src/MaxAreaOfIsland.java

@@ -0,0 +1,28 @@
+public class MaxAreaOfIsland {
+
+    public int maxAreaOfIsland(int[][] grid) {
+        int[] area = new int[1];
+        int max = 0;
+
+        for (int i = 0; i < grid.length; i++) {
+            for (int j = 0; j < grid[0].length; j++) {
+                area[0] = 0;
+                dfs(grid, i, j, area);
+                max = Math.max(max, area[0]);
+            }
+        }
+        return max;
+    }
+
+    private void dfs(int[][] grid, int i, int j, int[] count) {
+        if (i < 0 || i >= grid.length || j < 0 || j >= grid[0].length || grid[i][j] != 1) {
+            return;
+        }
+        grid[i][j] = 0;
+        count[0]++;
+        dfs(grid, i + 1, j, count);
+        dfs(grid, i - 1, j, count);
+        dfs(grid, i, j + 1, count);
+        dfs(grid, i, j - 1, count);
+    }
+}

leetcode/solution/src/MoveZeroes.java

@@ -4,14 +4,16 @@
 public class MoveZeroes {
 
     /**
-     * 要保持顺序，写的次数最少
+     * 要保持顺序
      */
     public void moveZeroes(int[] nums) {
-        for (int i = 0, j = 0; j < nums.length; j++) {
-            if (nums[j] != 0) {
-                swap(nums, i++, j);
+        int j = 0;
+        for (int i = 0; i < nums.length; i++) {
+            if (nums[i] != 0) {
+                nums[j++] = nums[i];
             }
         }
+        for ( ; j < nums.length; nums[j++] = 0);
     }
 
     private void swap(int[] nums, int i, int j) {
@@ -22,6 +24,7 @@ private void swap(int[] nums, int i, int j) {
 
     /**
      * 如果不要求保持顺序，且写的次数最少
+     * 从两头开始往中间走，如果左边是0，右边非0，则交换，写的次数是0的个数乘2
      */
     public void moveZeroes2(int[] nums) {
         for (int i = 0, j = nums.length - 1; j > i; ) {

leetcode/solution/src/UniqueEmailAddresses.java

@@ -0,0 +1,25 @@
+import java.util.HashSet;
+import java.util.Set;
+
+public class UniqueEmailAddresses {
+
+    public int numUniqueEmails(String[] emails) {
+        Set<String> set = new HashSet<>();
+        for (String email : emails) {
+            set.add(make(email));
+        }
+        return set.size();
+    }
+
+    private String make(String email) {
+        int index = email.indexOf("@");
+        String host = email.substring(index + 1);
+        String name = email.substring(0, index);
+        int index2 = name.indexOf("+");
+        if (index2 >= 0) {
+            name = name.substring(0, index2);
+        }
+        name = name.replaceAll(".", "");
+        return name + "@" + host;
+    }
+}

leetcode/src/Main.java

@@ -2,26 +2,33 @@
 
 public class Main {
 
-    public int findCircleNum(int[][] M) {
-        int num = 0;
-        for (int i = 0; i < M.length; i++) {
-            if (M[i][i] == 1) {
-                dfs(M, i);
-                num++;
+    public int maxAreaOfIsland(int[][] grid) {
+        int[] area = new int[1];
+        int max = 0;
+
+        for (int i = 0; i < grid.length; i++) {
+            for (int j = 0; j < grid[0].length; j++) {
+                area[0] = 0;
+                dfs(grid, i, j, area);
+                max = Math.max(max, area[0]);
             }
         }
-        return num;
+        return max;
     }
 
-    private void dfs(int[][] M, int i) {
-        M[i][i] = 0;
-        for (int j = 0; j < M.length; j++) {
-            if (M[j][j] != 0 && M[i][j] == 1) {
-                dfs(M, j);
-            }
+    private void dfs(int[][] grid, int i, int j, int[] count) {
+        if (i < 0 || i >= grid.length || j < 0 || j >= grid[0].length || grid[i][j] != 1) {
+            return;
         }
+        grid[i][j] = 0;
+        count[0]++;
+        dfs(grid, i + 1, j, count);
+        dfs(grid, i - 1, j, count);
+        dfs(grid, i, j + 1, count);
+        dfs(grid, i, j - 1, count);
     }
 
     public static void main(String[] args) {
+
     }
 }