Compute maximum benefit possible by buying and selling an stock

StockBenefit.java

/* File:    StockBenefit.java
 * Created: 2018-04-04
 * Author:  Sabbir Manandhar
 *
 * Copyright (c) 2018 Hogwart Inc.
 */

/**
 * Compute potential max profit
 *
 * @author Sabbir Manandhar
 * @version 1.0
 */
public class StockBenefit {

  public static void main(String[] args) {
    int[] stocks = new int[] {10, 7, 5, 8, 11, 9};
    int profit = getMaxProfit(stocks);
    int expectedProfit = 6;
    verify(expectedProfit, profit);

    stocks = new int[] {15, 5, 10, 25, 55, 1};
    profit = getMaxProfit(stocks);
    expectedProfit = 50;
    verify(expectedProfit, profit);

    stocks = new int[] {10, 9, 8, 7, 6, 5};
    profit = getMaxProfit(stocks);
    expectedProfit = -1;
    verify(expectedProfit, profit);

    stocks = new int[] {10, 10, 10, 10, 10, 10};
    profit = getMaxProfit(stocks);
    expectedProfit = 0;
    verify(expectedProfit, profit);

    stocks = new int[] {10, 7, 5, 8, 11, 9};
    profit = getMaxProfit_2(stocks);
    expectedProfit = 6;
    verify(expectedProfit, profit);

    stocks = new int[] {15, 5, 10, 25, 55, 1};
    profit = getMaxProfit_2(stocks);
    expectedProfit = 50;
    verify(expectedProfit, profit);

    stocks = new int[] {10, 9, 8, 7, 6, 5};
    profit = getMaxProfit_2(stocks);
    expectedProfit = -1;
    verify(expectedProfit, profit);

    stocks = new int[] {10, 10, 10, 10, 10, 10};
    profit = getMaxProfit_2(stocks);
    expectedProfit = 0;
    verify(expectedProfit, profit);
  } // main

  //-------------------------------------------------------------------------------------

  /**
   * Assertion method to verify two values
   * @param expected
   * @param actual
   */
  public static void verify(int expected, int actual) {
    if (expected != actual) throw new AssertionError();
  } // verify

  //-------------------------------------------------------------------------------------

  /**
   * Brute Force Approach to calculate the profit
   * @param stockPrices input stock prices
   * @return max profit
   */
  public static int getMaxProfit(int[] stockPrices) {
    int maxProfit = Integer.MIN_VALUE;

    for (int i = 0; i < stockPrices.length; i++) {
      for (int j = i+1; j < stockPrices.length; j++) {
        int profit = stockPrices[j] - stockPrices[i];
        if (profit > maxProfit) {
          maxProfit = profit;
        }
      }
    }

    return maxProfit;
  } // getMaxProfit

  //-------------------------------------------------------------------------------------

  /**
   * Linear Time solution to find the max profit
   * @param stockPrices input stock prices
   * @return max profit
   */
  public static int getMaxProfit_2(int[] stockPrices) {
    int maxProfit = Integer.MIN_VALUE;
    int minPrice = stockPrices[0];

    for (int i = 1; i < stockPrices.length; i++) {
      int profit = stockPrices[i] - minPrice;
      if (maxProfit < profit) {
        maxProfit = profit;
      }

      if (minPrice > stockPrices[i]) {
        minPrice = stockPrices[i];
      }

    }
    return maxProfit;
  } // getMaxProfit_2

} // StockBenefit