Has anyone here worked on the algorithms that financial institutions use to trade? How is it possible that the S&P 500 went from -2% to +3%?

The news was that Trump allegedly was talking about a tarrif pause for 90 days. The S&P 500 skyrockets in a few minutes microseconds after this news is announced.

Are there any people in the industry here who have first hand experience coding these "mythical" algorithms that everyone talks about? How can they know the news so quickly. Is there any evidence it is caused by these algorithms?