Add solution #376

Author: JoshCrozier

0376-wiggle-subsequence.js

@@ -0,0 +1,39 @@
+/**
+ * 376. Wiggle Subsequence
+ * https://leetcode.com/problems/wiggle-subsequence/
+ * Difficulty: Medium
+ *
+ * A wiggle sequence is a sequence where the differences between successive numbers strictly
+ * alternate between positive and negative. The first difference (if one exists) may be either
+ * positive or negative. A sequence with one element and a sequence with two non-equal elements
+ * are trivially wiggle sequences.
+ * - For example, [1, 7, 4, 9, 2, 5] is a wiggle sequence because the differences (6, -3, 5, -7, 3)
+ *   alternate between positive and negative.
+ * - In contrast, [1, 4, 7, 2, 5] and [1, 7, 4, 5, 5] are not wiggle sequences. The first is not
+ *   because its first two differences are positive, and the second is not because its last
+ *   difference is zero.
+ *
+ * A subsequence is obtained by deleting some elements (possibly zero) from the original sequence,
+ * leaving the remaining elements in their original order.
+ *
+ * Given an integer array nums, return the length of the longest wiggle subsequence of nums.
+ */
+
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var wiggleMaxLength = function(nums) {
+  let up = 1;
+  let down = 1;
+
+  for (let i = 1; i < nums.length; i++) {
+    if (nums[i] > nums[i - 1]) {
+      up = down + 1;
+    } else if (nums[i] < nums[i - 1]) {
+      down = up + 1;
+    }
+  }
+
+  return Math.max(up, down);
+};

README.md

@@ -295,6 +295,7 @@
 373|[Find K Pairs with Smallest Sums](./0373-find-k-pairs-with-smallest-sums.js)|Medium|
 374|[Guess Number Higher or Lower](./0374-guess-number-higher-or-lower.js)|Medium|
 375|[Guess Number Higher or Lower II](./0375-guess-number-higher-or-lower-ii.js)|Medium|
+376|[Wiggle Subsequence](./0376-wiggle-subsequence.js)|Medium|
 378|[Kth Smallest Element in a Sorted Matrix](./0378-kth-smallest-element-in-a-sorted-matrix.js)|Medium|
 380|[Insert Delete GetRandom O(1)](./0380-insert-delete-getrandom-o1.js)|Medium|
 383|[Ransom Note](./0383-ransom-note.js)|Easy|