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Count the Duplicates (LeetCode Problem-Solving — 2)
2 min readJan 12, 2025
“Count the duplicate number” problem: Count the duplicate values in the array, by modifying the containsDuplicate function from the blog Contains Duplicate (Problem-Solving — 1) to track how many times each number appears.
We will be using a Map or a plain JavaScript Object.
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If you haven’t read the “Duplicate Check” problem yet, I highly recommend reading it first before diving into this problem for a better understanding of the context.
Let’s Start…
1 — Count the duplicates:
Here is the modified function of containsDuplicate to count the duplicates, the output is a variable duplicateCount and will return how many values appear more than once:
