Feat: 54. Spiral Matrix

spiral-matrix/HC-kang.ts

@@ -0,0 +1,44 @@
+/**
+ * https://leetcode.com/problems/spiral-matrix
+ * T.C. O(m * n)
+ * S.C. O(m * n)
+ */
+function spiralOrder(matrix: number[][]): number[] {
+  const clockwise = [
+    [0, 1],
+    [1, 0],
+    [0, -1],
+    [-1, 0],
+  ];
+  let currentDirection = 0;
+
+  const visited = new Array(matrix.length)
+    .fill(0)
+    .map(() => new Array(matrix[0].length).fill(false));
+
+  const result: number[] = [];
+
+  let row = 0;
+  let col = 0;
+
+  while (result.length < matrix.length * matrix[0].length) {
+    result.push(matrix[row][col]);
+    visited[row][col] = true;
+
+    const nextRow = row + clockwise[currentDirection][0];
+    const nextCol = col + clockwise[currentDirection][1];
+
+    if (
+      nextRow < 0 || nextRow >= matrix.length ||
+      nextCol < 0 || nextCol >= matrix[0].length ||
+      visited[nextRow][nextCol]
+    ) {
+      currentDirection = (currentDirection + 1) % 4;
+    }
+
+    row += clockwise[currentDirection][0];
+    col += clockwise[currentDirection][1];
+  }
+
+  return result;
+}