finish 59

Author: BaffinLee

59. Spiral Matrix II.js

@@ -0,0 +1,44 @@
+/**
+ * 59. Spiral Matrix II
+ * 
+ * Given a positive integer n, generate a square matrix filled with elements from 1 to n2 in spiral order.
+ * 
+ * Example:
+ * 
+ * Input: 3
+ * Output:
+ * [
+ *  [ 1, 2, 3 ],
+ *  [ 8, 9, 4 ],
+ *  [ 7, 6, 5 ]
+ * ]
+ */
+
+/**
+ * @param {number} n
+ * @return {number[][]}
+ */
+var generateMatrix = function(n) {
+	var x1 = 0;
+	var x2 = n - 1;
+	var y1 = 0;
+	var y2 = n - 1;
+	var i = 0;
+	var res = Array(n).fill(0).map(_ => Array(n));
+	while (x1 <= x2 && y1 <= y2) {
+			for (var x = x1; x <= x2; x++) res[y1][x] = ++i;
+			for (var y = y1 + 1; y <= y2; y++) res[y][x2] = ++i;
+			for (var x = x2 - 1; x > x1; x--) res[y2][x] = ++i;
+			for (var y = y2; y > y1; y--) res[y][x1] = ++i;
+			x1++;
+			x2--;
+			y1++;
+			y2--;
+	}
+	return res;
+};
+
+// 绕圈，1 => 2 => 3 => 4 => 5
+// 111
+// 452
+// 432