Traditional Stock Buy Sell Problem

buySell.js

/*
 * Problem: Transaction in k
 * List the days to buy and days to sell
 * Complexity
 * p = prices
 * k = transactions
 *
 * O(p + k)
 */
const daysToSell = (prices, k) => {
  const buySellDays = []
  let minMaxBool = true
  let profit = 0
  // count how many transactions have been pushed
  let i = 0;
  prices.forEach((price, day) => {
    if (prices.length - 1 === day) {
      if (!minMaxBool) {
        buySellDays[i].sellDay = day
        buySellDays[i].localProfit = prices[day] - prices[buySellDays[i].buyDay]
        profit = profit + prices[day]
      } 
      // last day reached
      return;
    }
    if (minMaxBool) {
      // look for min
      if (price < prices[day + 1]) {
        buySellDays[i] = {'buyDay': day}
        minMaxBool = false
        profit = profit - prices[day]
      }
    } else {
      if (price > prices[day + 1]) {
        profit = profit + prices[day]
        buySellDays[i].sellDay = day
        buySellDays[i].localProfit = prices[day] - prices[buySellDays[i].buyDay]
        i++
        minMaxBool = true
      }
    }
  })

  buySellDays.sort((tranA, tranB) => {
    return tranA.localProfit < tranB.localProfit
  })

  const limitedTransactions = buySellDays.slice(0, k)
  const limitedProfits = limitedTransactions.reduce((total, transaction) => {
    return total + transaction.localProfit
  }, 0)

  return {'transactions': buySellDays.slice(0, k), 'totalProfit': limitedProfits}
}

const prices = [2, 5, 7, 1, 4, 3, 1, 3]
console.log(daysToSell(prices1, 3))

I wouldn't use this. There is a bug in this. Doesn't work in this set of data
const prices = [2, 5, 7, 1, 4, 3, 2, 20]