Nachiket and Supernova

Nachiket was so fond of supernova, that he built a spaceship to travel through space. But soon he came to know that the location of supernova is hidden in the patterns of galaxies near it. He knew the number of galaxies is $N$ in his universe, the $i^{th}$ galaxy is located at co-ordinate $i$ and has power level $A_i$. - if $A_i$ is greater than zero we say the galaxy is made up of ordinary matt