adventOfCode-2015-day7.js

const {map, pipe} = require('ramda');                                    
                                                                         
const operations = {                                                     
  NOT: a => ~a,                                                          
  COPY: a => a,                                                          
  AND: (a, b) => a & b,                                                  
  OR: (a, b) => a | b,                                                   
  LSHIFT: (a, b) => a << b,                                              
  RSHIFT: (a, b) => a >> b,                                              
};                                                                       
                                                                         
const parseLine = line => {                                              
  const [instruction, to] = line.split(' -> ');                          
  if (instruction.startsWith('NOT')) {                                   
    const [, a] = instruction.split(' ');                                
    return {operation: 'NOT', a, to};                                    
  }                                                                      
  if (instruction.indexOf(' ') === -1) {                                 
    return {operation: 'COPY', a: instruction, to};                      
  }                                                                      
  const [, a, operation, b] = instruction.match(/(\w*) (\w*) (\w*)/);    
  return {operation, a, b, to};                                          
};                                                                       
                                                                         
const connectWire = wires => {                                           
  const getValue = x => {                                                
    const n = parseInt(x);                                               
    if (!Number.isNaN(n)) return n;                                      
    const wireVal = wires[x];                                            
    return typeof wireVal === 'function' ? wireVal() : wireVal;          
  };                                                                     
  return ({operation, a: a_, b: b_, to}) => {                            
    wires[to] = () => {                                                  
      const [a, b] = [a_, b_].filter(x => x !== undefined).map(getValue);
      return (wires[to] = operations[operation](a, b));                  
    };                                                                   
  };                                                                     
};                                                                       
                                                                         
const solution1 = pipe(                                                  
  map(parseLine),                                                        
  parsedLines => {                                                       
    const wires = {};                                                    
    parsedLines.forEach(connectWire(wires));                             
    return wires.a();                                                    
  }                                                                      
);                                                                       
                                                                         
const solution2 = pipe(                                                  
  map(parseLine),                                                        
  parsedLines => {                                                       
    const wires = {};                                                    
    const copy = {};                                                     
    parsedLines.forEach(connectWire(wires));                             
    parsedLines.forEach(connectWire(copy));                              
    copy.b = wires.a();                                                  
    return copy.a();                                                     
  }                                                                      
);                                                                       
                                                                         
module.exports = [solution1, solution2];