update: 376

Author: hijiangtao

README.md

@@ -104,6 +104,7 @@ This is the solutions collection of my LeetCode submissions, most of them are pr
 |342|[Power of Four](https://leetcode.com/problems/power-of-four/) | [JavaScript](./src/power-of-four/res.js)|Easy|
 |344|[Reverse String](https://leetcode.com/problems/reverse-string/) | [JavaScript](./src/reverse-string/res.js)|Easy|
 |371|[Sum of Two Integers](https://leetcode.com/problems/sum-of-two-integers/) | [JavaScript](./src/sum-of-two-integers/res.js)|Easy|
+|376|[Wiggle Subsequence](https://leetcode.com/problems/wiggle-subsequence/) | [JavaScript](./src/wiggle-subsequence/res.js)|Medium|
 |384|[Shuffle an Array](https://leetcode.com/problems/shuffle-an-array/) | [JavaScript](./src/shuffle-an-array/res.js)|Medium|
 |404|[Sum of Left Leaves](https://leetcode.com/problems/sum-of-left-leaves/) | [JavaScript](./src/sum-of-left-leaves/res.js)|Easy|
 |413|[Arithmetic Slices](https://leetcode.com/problems/arithmetic-slices/) | [JavaScript](./src/arithmetic-slices/res.js)|Medium|

src/wiggle-subsequence/res.js

@@ -0,0 +1,21 @@
+/**
+* @param {number[]} nums
+* @return {number}
+*/
+var wiggleMaxLength = function(nums) {
+const len = nums.length;
+if (len < 2) return nums.length;
+
+let prediff = nums[1] - nums[0];
+let count = prediff ? 2 : 1;
+
+for (let i = 2; i < len; i++) {
+const flag = nums[i] - nums[i-1];
+if (flag > 0 && prediff <= 0 || flag < 0 && prediff >= 0) {
+count++;
+prediff = flag;
+}
+}
+
+return count;
+};