AoC 2019 - day 6

AoC_2019_d6.js

const INPUT = `
COPY & PASTE HERE
`.trim``.split`\n`;
// prepare orbit map
INPUT.map(x=>o[[s,y]=x.split`)`,y]=s,o={}); // o == all orbits
// Part 1
c={}; // cache
a=k=>c[k]||(o[k]?c[k]=1+a(o[k]):0); // get all orbiters count
t=Object.keys(o).reduce((t,c)=>t+a(c),0); // count total
// Part 2
b=k=>(s=o[k])?[s,...b(s)]:[]; // get all orbits up to K
Y=b('YOU'); // all orbits up to YOU
S=b('SAN'); // all orbits up to SANTA
d=(f=i=>~(x=S.findIndex(s=>s==Y[i]))?x-+-i:f(i+1))(0); // get orbit jump count
//