Create index.ts

Author: masx200

wiggle-subsequence/index.ts

@@ -0,0 +1,18 @@
+function wiggleMaxLength(nums: number[]): number {
+
+    const n = nums.length;
+    if (n < 2) {
+        return n;
+    }
+    let prevdiff = nums[1] - nums[0];
+    let ret = prevdiff !== 0 ? 2 : 1;
+    for (let i = 2; i < n; i++) {
+        const diff = nums[i] - nums[i - 1];
+        if ((diff > 0 && prevdiff <= 0) || (diff < 0 && prevdiff >= 0)) {
+            ret++;
+            prevdiff = diff;
+        }
+    }
+    return ret;
+}
+export default wiggleMaxLength