lc: add solution for alternating groups II

Author: electyrion

src/main/java/com/thealgorithms/leetcode/slidingwindow/alternatinggroupsII/Solution.java

@@ -0,0 +1,14 @@
+package com.thealgorithms.leetcode.slidingwindow.alternatinggroupsII;
+
+public class Solution {
+    public int numberOfAlternatingGroups(int[] colors, int k) {
+        int n = colors.length, res = 0, count = 1;
+        for (int i = 0; i < n + k - 2; i++) {
+            count = colors[i % n] != colors[(i + 1) % n] ? count + 1 : 1;
+            res += count >= k ? 1 : 0;
+        }
+        return res;
+    }
+}
+
+// https://leetcode.com/problems/alternating-groups-ii/?envType=daily-question&envId=2025-03-09