Cheaper oil prices will reduce inflation in the U.S. and that's quite positive for the U.S. economy.
No matter when the BOJ scraps quantitative easing, the move should be considered positive because that shows the central bank sees Japan's economy as solid enough to bear that.
The Fed minutes were a positive surprise as investors hadn't anticipated an end to interest rate increases at the time of the meeting. With strong earnings results both at home and in the U.S., all the good news came out at the same time and encouraged investors to bet on stocks.