Add solution #959

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,044 LeetCode solutions in JavaScript
+# 1,045 LeetCode solutions in JavaScript
 
 [https://leetcode.com/](https://leetcode.com/)
 
@@ -768,6 +768,7 @@
 956|[Tallest Billboard](./solutions/0956-tallest-billboard.js)|Hard|
 957|[Prison Cells After N Days](./solutions/0957-prison-cells-after-n-days.js)|Medium|
 958|[Check Completeness of a Binary Tree](./solutions/0958-check-completeness-of-a-binary-tree.js)|Medium|
+959|[Regions Cut By Slashes](./solutions/0959-regions-cut-by-slashes.js)|Medium|
 966|[Vowel Spellchecker](./solutions/0966-vowel-spellchecker.js)|Medium|
 970|[Powerful Integers](./solutions/0970-powerful-integers.js)|Easy|
 976|[Largest Perimeter Triangle](./solutions/0976-largest-perimeter-triangle.js)|Easy|

solutions/0959-regions-cut-by-slashes.js

@@ -0,0 +1,59 @@
+/**
+ * 959. Regions Cut By Slashes
+ * https://leetcode.com/problems/regions-cut-by-slashes/
+ * Difficulty: Medium
+ *
+ * An n x n grid is composed of 1 x 1 squares where each 1 x 1 square consists of
+ * a '/', '\', or blank space ' '. These characters divide the square into contiguous
+ * regions.
+ *
+ * Given the grid grid represented as a string array, return the number of regions.
+ *
+ * Note that backslash characters are escaped, so a '\' is represented as '\\'.
+ */
+
+/**
+ * @param {string[]} grid
+ * @return {number}
+ */
+var regionsBySlashes = function(grid) {
+  const size = grid.length * 3;
+  const matrix = new Array(size).fill().map(() => new Array(size).fill(0));
+
+  for (let row = 0; row < grid.length; row++) {
+    for (let col = 0; col < grid.length; col++) {
+      const baseRow = row * 3;
+      const baseCol = col * 3;
+      if (grid[row][col] === '/') {
+        matrix[baseRow][baseCol + 2] = 1;
+        matrix[baseRow + 1][baseCol + 1] = 1;
+        matrix[baseRow + 2][baseCol] = 1;
+      } else if (grid[row][col] === '\\') {
+        matrix[baseRow][baseCol] = 1;
+        matrix[baseRow + 1][baseCol + 1] = 1;
+        matrix[baseRow + 2][baseCol + 2] = 1;
+      }
+    }
+  }
+
+  let result = 0;
+  for (let row = 0; row < size; row++) {
+    for (let col = 0; col < size; col++) {
+      if (matrix[row][col] === 0) {
+        helper(row, col);
+        result++;
+      }
+    }
+  }
+
+  return result;
+
+  function helper(x, y) {
+    if (x < 0 || x >= size || y < 0 || y >= size || matrix[x][y] !== 0) return;
+    matrix[x][y] = 1;
+    helper(x + 1, y);
+    helper(x - 1, y);
+    helper(x, y + 1);
+    helper(x, y - 1);
+  }
+};