In Salesforce, Person Accounts are found simultaneously in both Account and Contact objects. Analyzing and merging these dupes in Accounts (Person Account) will also resolve the duplicates found in Contacts.
Note: Salesforce does not allow merging Contacts of type Person Accounts. To exclude such Contact objects from analysis we recommend adding the following filter to the Contacts dataset (using Advanced SOQL switch)
Account.isPersonAccount = FALSE
We also recommend having another dataset Person Accounts with the following filter
isPersonAccount = TRUE