I just wonder, living cost in every country is different, so does adsense differentiate the payment for people in different country?
Yes Google pay different click rates for every country its depends upon the adwords campaign how much advertiser has putted his per click rate for specific country
google does not influence the $ amount one bit. the price is set by the bidders (the advertisers). eventually, the CPC will vary from country to country because the local economies vary also. the good thing is that the location of the publisher doesn't matter
For Adsense® the country of residence does not matter, but for Adwords® it does, every advertiser places bids in his own currency rate (Converted to USD as displayed in publishers reports [as income generated])
Don`t matter YOUR country, it matters visitors that click ads country, and of course advertisers campaign.