Add solution #3070

Author: JoshCrozier

README.md

@@ -2155,6 +2155,7 @@
 3067|[Count Pairs of Connectable Servers in a Weighted Tree Network](./solutions/3067-count-pairs-of-connectable-servers-in-a-weighted-tree-network.js)|Medium|
 3068|[Find the Maximum Sum of Node Values](./solutions/3068-find-the-maximum-sum-of-node-values.js)|Hard|
 3069|[Distribute Elements Into Two Arrays I](./solutions/3069-distribute-elements-into-two-arrays-i.js)|Easy|
+3070|[Count Submatrices with Top-Left Element and Sum Less Than k](./solutions/3070-count-submatrices-with-top-left-element-and-sum-less-than-k.js)|Medium|
 3105|[Longest Strictly Increasing or Strictly Decreasing Subarray](./solutions/3105-longest-strictly-increasing-or-strictly-decreasing-subarray.js)|Easy|
 3108|[Minimum Cost Walk in Weighted Graph](./solutions/3108-minimum-cost-walk-in-weighted-graph.js)|Hard|
 3110|[Score of a String](./solutions/3110-score-of-a-string.js)|Easy|

solutions/3070-count-submatrices-with-top-left-element-and-sum-less-than-k.js

@@ -0,0 +1,39 @@
+/**
+ * 3070. Count Submatrices with Top-Left Element and Sum Less Than k
+ * https://leetcode.com/problems/count-submatrices-with-top-left-element-and-sum-less-than-k/
+ * Difficulty: Medium
+ *
+ * You are given a 0-indexed integer matrix grid and an integer k.
+ *
+ * Return the number of submatrices that contain the top-left element of the grid, and have a sum
+ * less than or equal to k.
+ */
+
+/**
+ * @param {number[][]} grid
+ * @param {number} k
+ * @return {number}
+ */
+var countSubmatrices = function(grid, k) {
+  const rows = grid.length;
+  const cols = grid[0].length;
+  const prefixSum = Array.from({ length: rows + 1 }, () => new Array(cols + 1).fill(0));
+
+  for (let i = 1; i <= rows; i++) {
+    for (let j = 1; j <= cols; j++) {
+      prefixSum[i][j] = grid[i-1][j-1] + prefixSum[i-1][j]
+        + prefixSum[i][j-1] - prefixSum[i-1][j-1];
+    }
+  }
+
+  let result = 0;
+  for (let i = 1; i <= rows; i++) {
+    for (let j = 1; j <= cols; j++) {
+      if (prefixSum[i][j] <= k) {
+        result++;
+      }
+    }
+  }
+
+  return result;
+};