From 3334cb2b268e6c7cf2dca19604323e04601244b4 Mon Sep 17 00:00:00 2001
From: Chhavi Bansal <chh@adobe.com>
Date: Sun, 2 Oct 2022 18:13:29 +0530
Subject: [PATCH] [2428] Maximise Hour glass sum

---
 .../Algorithms/Maximise_Hour_Glass_Sum.js     | 48 +++++++++++++++++++
 .../Algorithms/Maximise_Hour_Glass_Sum.js     |  9 ++++
 README.md                                     |  1 +
 3 files changed, 58 insertions(+)
 create mode 100644 LeetcodeProblems/Algorithms/Maximise_Hour_Glass_Sum.js
 create mode 100644 LeetcodeProblemsTests/Algorithms/Maximise_Hour_Glass_Sum.js

diff --git a/LeetcodeProblems/Algorithms/Maximise_Hour_Glass_Sum.js b/LeetcodeProblems/Algorithms/Maximise_Hour_Glass_Sum.js
new file mode 100644
index 0000000..124d4a2
--- /dev/null
+++ b/LeetcodeProblems/Algorithms/Maximise_Hour_Glass_Sum.js
@@ -0,0 +1,48 @@
+/*
+2428. Maximum Sum of an Hourglass
+
+You are given an m x n integer matrix grid.
+We define an hourglass as a part of the matrix with the following form:
+For Input : [[6,2,1],[4,2,1],[9,2,8]]
+The Hourglass sum would be => 6 + 2 + 1 + 2( 2nd row , 2nd column) + 9 + 2 + 8
+
+Return the maximum sum of the elements of an hourglass.
+
+Note that an hourglass cannot be rotated and must be entirely contained within the matrix.
+
+Constraints:
+
+m == grid.length
+n == grid[i].length
+3 <= m, n <= 150
+0 <= grid[i][j] <= 106
+
+Input: grid = [[6,2,1,3],[4,2,1,5],[9,2,8,7],[4,1,2,9]]
+Output: 30
+Explanation: The cells shown above represent the hourglass with the maximum sum: 6 + 2 + 1 + 2 + 9 + 2 + 8 = 30.
+
+
+Input: grid = [[1,2,3],[4,5,6],[7,8,9]]
+Output: 35
+Explanation: There is only one hourglass in the matrix, with the sum: 1 + 2 + 3 + 5 + 7 + 8 + 9 = 35.
+*/
+
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+ var maxSum = function(grid) {
+  const m = grid.length;
+  const n = grid[0].length;
+  if(m<3 || n < 3) {
+      return 0;
+  }
+  let max = 0;
+  for(let i = 0; i<m-2; i++)
+      for(let j = 0; j<n-2;j++)
+      {
+          let cur = grid[i][j] + grid[i][j+1] + grid[i][j+2] + grid[i+1][j+1] + grid[i+2][j] + grid[i+2][j+1] + grid[i+2][j+2];
+          max = Math.max(cur, max);
+      }
+  return max;  
+};
\ No newline at end of file
diff --git a/LeetcodeProblemsTests/Algorithms/Maximise_Hour_Glass_Sum.js b/LeetcodeProblemsTests/Algorithms/Maximise_Hour_Glass_Sum.js
new file mode 100644
index 0000000..b612df0
--- /dev/null
+++ b/LeetcodeProblemsTests/Algorithms/Maximise_Hour_Glass_Sum.js
@@ -0,0 +1,9 @@
+const assert = require('assert');
+const maxSum = require('../../LeetcodeProblems/Algorithms/Maximise_Hour_Glass_Sum').maxSum;
+
+function test() {
+  assert.equal(maxSum([[6,2,1,3],[4,2,1,5],[9,2,8,7],[4,1,2,9]]));
+  assert.equal(maxSum([[1,2,3],[4,5,6],[7,8,9]]));
+}
+
+module.exports.test = test
diff --git a/README.md b/README.md
index 9702e81..6085d84 100644
--- a/README.md
+++ b/README.md
@@ -61,6 +61,7 @@ To run a specific problem in your console run  `node <problem_file_path>` (e.g.
 | [Verify Preorder Serialization of a Binary Tree ](/LeetcodeProblems/Algorithms/Verify_Preorder_Serialization_of_a_Binary_Tree.js)              | Medium | https://leetcode.com/problems/verify-preorder-serialization-of-a-binary-tree/ |
 | [Construct Binary Tree from Preorder and Inorder Traversal ](/LeetcodeProblems/Algorithms/Construct_Binary_Tree_from_Preorder_and_Inorder_Traversal.js)   | Medium | https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/ | 
 | [Lowest Common Ancestor of a Binary Tree ](/LeetcodeProblems/Algorithms/Lowest_Common_Ancestor_of_a_Binary_Tree.js) | Medium | https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/ |
+| [Maximum Sum of an Hourglass](/LeetcodeProblems/Algorithms/Maximise_Hour_Glass_Sum.js)                          | Medium | https://leetcode.com/problems/maximum-sum-of-an-hourglass/ |
 | [Flood Fill ](/LeetcodeProblems/Algorithms/Flood_Fill.js)                                                       | Easy   | https://leetcode.com/problems/flood-fill/ |
 | [Implement stack using queues ](/LeetcodeProblems/Algorithms/Implement_stack_using_queues.js)                   | Easy   | https://leetcode.com/problems/implement-stack-using-queues/ |
 | [Number of Segments in a String ](/LeetcodeProblems/Algorithms/Number_of_Segments_in_a_String.js)               | Easy   | https://leetcode.com/problems/number-of-segments-in-a-string/ |