5. Spiral Matrix

Author: Sunjae95

spiral-matrix/sunjae95.js

@@ -0,0 +1,45 @@
+/**
+ * @description
+ * brainstorming:
+ * just implement question
+ *
+ * m: length of matrix
+ * n: length of matrix[i]
+ * time complexity: O(m * n)
+ * space complexity: O(m * n)
+ */
+var spiralOrder = function (matrix) {
+  let count = matrix.length * matrix[0].length;
+  let [r, c] = [1, 1];
+  const answer = [];
+  const MAX_R = matrix.length + 2;
+  const MAX_C = matrix[0].length + 2;
+  const visited = Array.from({ length: MAX_R }, (_, i) => {
+    return Array.from(
+      { length: MAX_C },
+      (_, j) => i === 0 || i === MAX_R - 1 || j === 0 || j === MAX_C - 1
+    );
+  });
+
+  while (count--) {
+    const check = {
+      left: c >= 1 && visited[r][c - 1],
+      right: c < MAX_C - 1 && visited[r][c + 1],
+      top: r >= 1 && visited[r - 1][c],
+      bottom: r < MAX_R - 1 && visited[r + 1][c],
+    };
+    visited[r][c] = true;
+    answer.push(matrix[r - 1][c - 1]);
+
+    if (check.left && check.top && check.bottom) c++;
+    else if (check.left && check.top && check.right) r++;
+    else if (check.right && check.top && check.bottom) c--;
+    else if (check.left && check.right && check.bottom) r--;
+    else if (check.left && check.top) c++;
+    else if (check.top && check.right) r++;
+    else if (check.right && check.bottom) c--;
+    else if (check.bottom && check.left) r--;
+  }
+
+  return answer;
+};