Hackerrank - Hand shake - Javascript

handshake.js

/**
 * Hackerrank Solution - Handshake
 */
function main() {
  var T = parseInt(readLine());
  for(var a0 = 0; a0 < T; a0++){
    var N = parseInt(readLine());
    console.log(Math.floor(N * (N - 1)/2));
  }
}