feat: 每日一题答案

Author: luzhipeng

Diff for: daily/answers/54.spiral-matrix.js

@@ -0,0 +1,40 @@
+/*
+ * @lc app=leetcode id=54 lang=javascript
+ *
+ * [54] Spiral Matrix
+ */
+/**
+ * @param {number[][]} matrix
+ * @return {number[]}
+ */
+var spiralOrder = function(matrix) {
+  // https://leetcode.com/problems/spiral-matrix/discuss/20570/Clean-Java-readable-human-friendly-code
+  // brilliant!
+  const res = [];
+  if (matrix.length == 0) return res;
+
+  let top = 0;
+  let bottom = matrix.length - 1;
+  let left = 0;
+  let right = matrix[0].length - 1;
+
+  while (true) {
+    for (let i = left; i <= right; i++) res.push(matrix[top][i]);
+    top++;
+    if (top > bottom) break;
+
+    for (let i = top; i <= bottom; i++) res.push(matrix[i][right]);
+    right--;
+    if (left > right) break;
+
+    for (let i = right; i >= left; i--) res.push(matrix[bottom][i]);
+    bottom--;
+    if (top > bottom) break;
+
+    for (let i = bottom; i >= top; i--) res.push(matrix[i][left]);
+    left++;
+    if (left > right) break;
+  }
+
+  return res;
+};