Add solution #54

Author: JoshCrozier

README.md

@@ -11,6 +11,7 @@
 31|[Next Permutation](./0031-next-permutation.js)|Medium|
 36|[Valid Sudoku](./0036-valid-sudoku.js)|Medium|
 43|[Multiply Strings](./0043-multiply-strings.js)|Medium|
+54|[Spiral Matrix](./0054-spiral-matrix.js)|Medium|
 58|[Length of Last Word](./0058-length-of-last-word.js)|Easy|
 66|[Plus One](./0066-plus-one.js)|Easy|
 67|[Add Binary](./0067-add-binary.js)|Easy|

solutions/0054-spiral-matrix.js

@@ -0,0 +1,43 @@
+/**
+ * 54. Spiral Matrix
+ * https://leetcode.com/problems/spiral-matrix/
+ * Difficulty: Medium
+ *
+ * Given an `m x n` `matrix`, return all elements of the `matrix` in spiral order.
+ */
+
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var spiralOrder = function(matrix) {
+  const output = [];
+  let top = 0;
+  let right = matrix[0].length - 1;
+  let bottom = matrix.length - 1;
+  let left = 0;
+
+  while (output.length < matrix.length * matrix[0].length) {
+    for (let i = left; i <= right; i++) {
+      output.push(matrix[top][i]);
+    }
+    top++;
+
+    for (let i = top; i <= bottom; i++) {
+      output.push(matrix[i][right]);
+    }
+    right--;
+
+    for (let i = right; top <= bottom && i >= left; i--) {
+      output.push(matrix[bottom][i]);
+    }
+    bottom--;
+
+    for (let i = bottom; left <= right && i >= top; i--) {
+      output.push(matrix[i][left]);
+    }
+    left++;
+  }
+
+  return output;
+};