This one's in Drop D and starts.
They use a piano and a heavy analog synth to make a nice full sound.
Here's how to play it on guitar.

Intro/Verses
e----------------|
b----------------|
g----------------|
d----------------|
a--2--3---2--3-1-|
d----------------|      and repeats

e---------------------------------|
b---------------------------------|
g---------------------------------|
d---------------------------------|
a---------------------------------|
d--2--3---2--3-1---2--3---2--3-3--|

Pre Chorus

e--------------8--------------------------------8----------------11-(12121212-|
b------------------------------4----------------------------------------------|
g-----5-----5---------8-----8----------5-----5--------8-----8-----------------|
d-----------------------------------------------------------------------------|
a--3-----3---------6-----6----------3-----3--------6-----6--------------------|
d-----------------------------------------------------------------------------|

Chorus
  Are  Are  You The One?
e-----------------------|
b-----------------------|
g-----------------------|
d-----------------------|
a--2-3---2---3---1------|
d--------------------2--|

e1212121212121212
b----------------|
g----------------|
d----------------|
a----------------|
d----------------|        repeats through the whole chorus and links up after
                          the prechorus note at the 11th fret on the high E.

   That's it.
Rinse and Repeat.

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