[BOJ] 통계학

let input =require('fs').readFileSync('/dev/stdin').toString().trim().split('\n').map(e=>Number(e));
let n =input.shift();
let sum=0;

input.forEach(e=>sum+=e);
let avg= Math.round(sum/n);
if( avg===-0) avg=0;
console.log(avg)//산술평균
input.sort((a,b)=>a-b);
console.log(input[(1+n)/2-1])//중앙
let obj={};
input.forEach(e=>obj[e]=(obj[e]||0)+1);
let max=0;
let common=[];

for( key in obj){
  if (max<obj[key]){
    max=obj[key];
    common=[key];
  }
  else if(max===obj[key]){
    common.push(key);
  }
}
let common2=common.map(e => Number(e))
common2.sort((a,b)=>a-b)
// console.log(common2);
if(common2.length>=2) console.log(common2[1]);
else{
  console.log(common2.pop());//최빈값
}
if(input.length>=2){
console.log(input.pop()-input.shift());
}
else{console.log(0)}

Math.round의 결과가 -0일 수 있음에 유의..해야한다..