Create The Number of Beautiful Subsets.java

Author: vishnuthumpudi

The Number of Beautiful Subsets.java

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+class Solution {
+    public int beautifulSubsets(int[] nums, int k) {
+        
+        Map<Integer, Integer> m = new HashMap<>();
+
+        for (int num : nums) m.put(num, m.getOrDefault(num, 0) + 1);
+
+        int res = 1, prev = 0, prevPrev = 0;
+
+        for (Map.Entry<Integer, Integer> e : m.entrySet()) {
+            int cur = e.getKey();
+
+            if (m.containsKey(cur - k)) continue;
+            
+            prev = 0;
+
+            while (m.containsKey(cur)) {
+                prevPrev = prev;
+                prev = ((1 << m.get(cur)) - 1) * res;
+                res += prevPrev;
+                cur += k;
+            }
+            res += prev;
+        }
+        return res - 1;
+    }
+}