Add solution #695

Author: JoshCrozier

README.md

@@ -125,6 +125,7 @@
 648|[Replace Words](./0648-replace-words.js)|Medium|
 653|[Two Sum IV - Input is a BST](./0653-two-sum-iv-input-is-a-bst.js)|Easy|
 686|[Repeated String Match](./0686-repeated-string-match.js)|Easy|
+695|[Max Area of Island](./0695-max-area-of-island.js)|Medium|
 700|[Search in a Binary Search Tree](./0700-search-in-a-binary-search-tree.js)|Easy|
 701|[Insert into a Binary Search Tree](./0701-insert-into-a-binary-search-tree.js)|Medium|
 704|[Binary Search](./0704-binary-search.js)|Easy|

solutions/0695-max-area-of-island.js

@@ -0,0 +1,41 @@
+/**
+ * 695. Max Area of Island
+ * https://leetcode.com/problems/max-area-of-island/
+ * Difficulty: Medium
+ *
+ * You are given an m x n binary matrix grid. An island is a group of 1's (representing land)
+ * connected 4-directionally (horizontal or vertical.) You may assume all four edges of the
+ * grid are surrounded by water.
+ *
+ * The area of an island is the number of cells with a value 1 in the island.
+ *
+ * Return the maximum area of an island in grid. If there is no island, return 0.
+ */
+
+/**
+ * @param {number[][]} grid
+ * @return {number}
+ */
+var maxAreaOfIsland = function(grid) {
+  const cache = new Set();
+  let max = 0;
+
+  for (let i = 0; i < grid.length; i++) {
+    for (let j = 0; j < grid[0].length; j++) {
+      max = Math.max(max, traverse(grid, cache, i, j));
+    }
+  }
+
+  return max;
+};
+
+function traverse(grid, cache, x, y) {
+  let count = 0;
+  if (grid[x] && grid[x][y] === 1 && !cache.has(`${x},${y}`)) {
+    cache.add(`${x},${y}`);
+    count += [[x - 1, y], [x + 1, y], [x, y - 1], [x, y + 1]]
+      .map(([x, y]) => traverse(grid, cache, x, y))
+      .reduce((sum, count) => sum + count, 0) + 1;
+  }
+  return count;
+}