add new solutions

solutions/30/q3075/solution.go

@@ -0,0 +1,14 @@
+package q3075
+
+import "slices"
+
+func maximumHappinessSum(happiness []int, k int) int64 {
+	slices.Sort(happiness)
+	var sum int64
+	for i := range k {
+		sum += max(0, int64(happiness[len(happiness)-1-i]-i))
+	}
+	return sum
+}
+
+var _ = maximumHappinessSum