convert-currency-via-any

convert-currency-via-any.js

const main = () => {
	findExchangeRate([['USD', 'JPY', 110],['USD', 'AUD', 1.45],['JPY', 'GBP', 0.0070]], ['GBP', 'AUD'], 1)	
}

const findExchangeRate = (rates, toFrom, value) => {
  const to = toFrom[1];
  const from = toFrom[0];
	// build rate graph record
  const ratesGraph = {}
 	rates.map(rate => {
  	if(!ratesGraph[rate[0]]) ratesGraph[rate[0]] = {};
    if(!ratesGraph[rate[1]]) ratesGraph[rate[1]] = {};
  	ratesGraph[rate[0]][rate[1]] = rate[2];
    ratesGraph[rate[1]][rate[0]] = 1 / rate[2];
  })
  const visited = {}
  console.log(ratesGraph)
  console.log('res', findExchangeRateHelper(from, to, value, visited, ratesGraph));
}

const findExchangeRateHelper = (from, to, value, visited, ratesGraph) => {
  const currentRate = value;
  const queue = [];
  Object.keys(ratesGraph[from]).forEach(child => {
		queue.unshift([child, currentRate * ratesGraph[from][child] ]);
  });
      console.log(from);


  while (queue.length > 0) {
    const [currentNode, finalRate] = queue.pop();

    if(currentNode === to) return finalRate;
    if(!ratesGraph[currentNode]) return -1;
    
    console.log(currentNode, finalRate);

    visited[currentNode] = true;
    
    Object.keys(ratesGraph[currentNode]).forEach(child => {
	    const rate = ratesGraph[currentNode][child];

      if(!visited[child]) queue.unshift([child, finalRate * rate]);
    });
    
    
  }
  return -1;
}

main();