By Joyce Lee and Heekyong Yang SEOUL (Reuters) – Samsung Electronics Co Ltd on Thursday reported a 50% jump in quarterly operating earnings to post its highest first-quarter profit since 2018, as solid demand underpinned prices for memory chips. The world’s largest memory chip and smartphone maker estimated first-quarter profit at 14.1 trillion won ($11.6 billion), versus a Refinitiv SmartEstimate of 13.3 trillion won. Revenue likely rose 18% from the same period a year earlier to a record 77 trillion won, the company said in a short preliminary earnings release, also above market expectations…