content: package arrays;
  
  
  import com.sun.tools.javac.util.Pair;
  
  public class FindMaximumSellProfit {
  
      /*
       * Given an array representing prices of the stock on different days,
       * find the maximum profit that can be earned by performing maximum of one transaction.
       * A transaction consists of activity of buying and selling the stock on different or same days.
       *
       * Eg: 1 - {100, 80, 120, 130, 70, 60, 100, 125}
       * the price of the stock on day-1 is 100, on day-2 is 80 and so on.
       * The maximum profit that could be earned in this window is 65 (buy at 60 and sell at 125).
       *
       * Eg: 2 - For price array - {100, 80, 70, 65, 60, 55, 50}, maximum profit that could be earned is 0.
       *
       * */
  
  
      public static int findMaximumProfit(int[] stockPrices) {
          int minimumPrice = Integer.MAX_VALUE;
          int maxProfit = 0;
  
          /*
           * The profit is the maximum value of the maximumProfit so far and
           * the difference between the current element(selling price) and the minimum buying price - i.e. profit for that buy
           * Profit = current selling price - the minimum buying price
           *
           * Minimum buying price is the minimum value between the current element and the minimum price
           * */
          for(int i=0; i<stockPrices.length; i++) {
              maxProfit = Math.max(maxProfit, stockPrices[i]-minimumPrice);
              minimumPrice = Math.min(minimumPrice, stockPrices[i]);
          }
  
          return maxProfit;
      }
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
      public static Pair<Integer, Integer> findMaximumSellProfit(int length, int[] arr) {
          int currentBuy = arr[0];
          int globalSell = arr[1];
          int globalProfit = globalSell - currentBuy;
  
          int currentProfit;
  
          for(int i=1; i< length; i++) {
              int currentSell = arr[i];
              currentProfit = currentSell - currentBuy;
  
              if(currentProfit > globalProfit) {
                  globalProfit = currentProfit;
                  globalSell = arr[i];
              }
  
              if(currentBuy > arr[i]) {
                  currentBuy = arr[i];
              }
          }
  
          int optimalBuyPrice = globalSell-globalProfit;
          int optimalSellPrice = globalSell;
          return Pair.of(optimalBuyPrice, optimalSellPrice) ;
      }
  
  
  
  
  
      public static void main(String[] args) {
          int[] arr = {100, 80, 120, 130, 70, 60, 100, 125};
          System.out.println(findMaximumSellProfit(arr.length, arr));
          System.out.println(findMaximumProfit(arr));
      }
  }
  