Why can't intelliJ resolve this method?
It probably doesn't recognize the the latest Battlecode update. There's an icon with two blue arrows going in a circle, above the gradle tasks list. Clicking it will "Refresh All Gradle Projects" and hopefully fix your issue.
I am having the same problem in Eclipse. Previous updates have automatically worked... but I cannot get rc.getOpponentVictoryPoints() to work.
For Eclipse I think you can right click the project in the Package Explorer and select "Refresh Dependencies" in the "Gradle" menu