add 3000

Author: fishercoder1534

Diff for: paginated_contents/algorithms/4th_thousand/README.md

@@ -71,3 +71,4 @@
 | 3006 | [Find Beautiful Indices in the Given Array I](https://leetcode.com/problems/find-beautiful-indices-in-the-given-array-i/)                                           | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3006.java) |                                                                               | Medium     |
 | 3005 | [Count Elements With Maximum Frequency](https://leetcode.com/problems/count-elements-with-maximum-frequency/)                                                       | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3005.java) |                                                                               | Easy       |
 | 3004 | [Maximum Subtree of the Same Color](https://leetcode.com/problems/maximum-subtree-of-the-same-color/)                                                       | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3004.java) |                                                                               | Medium     | DFS, Tree
+| 3000 | [Maximum Area of Longest Diagonal Rectangle](https://leetcode.com/problems/maximum-area-of-longest-diagonal-rectangle/)                                                       | [Java](https://github.com/fishercoder1534/Leetcode/blob/master/src/main/java/com/fishercoder/solutions/fourththousand/_3000.java) |                                                                               | Easy       | 

Diff for: src/main/java/com/fishercoder/solutions/fourththousand/_3000.java

@@ -0,0 +1,22 @@
+package com.fishercoder.solutions.fourththousand;
+
+public class _3000 {
+    public static class Solution1 {
+        public int areaOfMaxDiagonal(int[][] dimensions) {
+            int ans = 0;
+            double maxDiagonal = 0.0;
+            for (int i = 0; i < dimensions.length; i++) {
+                int length = dimensions[i][0];
+                int width = dimensions[i][1];
+                double diagonal = Math.sqrt(length * length + width * width);
+                if (diagonal > maxDiagonal) {
+                    maxDiagonal = diagonal;
+                    ans = length * width;
+                } else if (diagonal == maxDiagonal && length * width > ans) {
+                    ans = length * width;
+                }
+            }
+            return ans;
+        }
+    }
+}