Although this song is in the key of D, the chord doesn't often appear. In the verse, the (A) chord functions as a (Dmaj7/9) with both the D and the F# implied. The main riff is two quaver triplets, or 6 notes in 2 beats. Where the timing is tricky, I've notated one chord for each two beats.

Note that Lorde's version from The Hunger Games is not a simple transposition, but includes parts of the song in the relative minor. You can get close by transposing the song to G, then in the verse replace (D) with (Em), and (C) with (Bm)