feat: 54. Spiral Matrix

Author: gwbaik9717

spiral-matrix/gwbaik9717.js

@@ -0,0 +1,52 @@
+// n: height of matrix, m: width of matrix
+// Time complexity: O(n*m)
+// Space complexity: O(n+m)
+
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var spiralOrder = function (matrix) {
+  const n = matrix.length;
+  const m = matrix[0].length;
+
+  // order of direction: East, South, West, North
+  const dy = [0, 1, 0, -1];
+  const dx = [1, 0, -1, 0];
+
+  let dir = 0;
+  let y = 0;
+  let x = 0;
+
+  const answer = [];
+
+  while (true) {
+    answer.push(matrix[y][x]);
+    matrix[y][x] = "";
+
+    let ny = y + dy[dir];
+    let nx = x + dx[dir];
+
+    if (ny >= 0 && ny < n && nx >= 0 && nx < m && matrix[ny][nx] !== "") {
+      y = ny;
+      x = nx;
+      continue;
+    }
+
+    // If the new position is out of bounds or already visited, Change direction
+    dir = (dir + 1) % 4;
+
+    ny = y + dy[dir];
+    nx = x + dx[dir];
+
+    // If the changed direction still has a problem, Break the loop
+    if (ny < 0 || ny >= n || nx < 0 || nx >= m || matrix[ny][nx] === "") {
+      break;
+    }
+
+    y = ny;
+    x = nx;
+  }
+
+  return answer;
+};