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🔁 Count Duplicates in List
❓ Problem Statement
Write a Python function that takes a list of integers and returns the number of duplicate values in it.
You should count each duplicated value only once, regardless of how many times it appears.
🔢 Input Format
📤 Output Format
✅ Constraints
- 1 ≤ Length of list ≤ 10^4
- -10^6 ≤ List elements ≤ 10^6
📌 Example Input
1 2 3 4 2 3 5 6 1
🎯 Example Output
🧩 Explanation
Duplicates are: 1, 2, 3 → count is 3
1 Answers
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To solve this, we convert the list into a set (to get unique values), and then count how many of those values appear more than once in the original list.
nums = list(map(int, input().split()))
print(len([x for x in set(nums) if nums.count(x) > 1]))
Input: 1 2 3 2 4 5 3 1
Output: 3
