// This program simulates making bets at a Roulette table.
// It assumes a European roulette table (no 00, which hurts the players odds)

import java.util.*;

public class Roulette {
	public static int WHEEL_SIZE = 37; // 0-36
	public static int RED_MIN = 1;
	public static int RED_MAX = 18;

	public static int INITIAL_MONEY = 500;

	public static int NUMBER_TRIALS = 10000; // better would be more trials for higher bets

   public static void main(String[] args) {
		Random r = new Random();
		System.out.println("Go for broke:");
		for(int i=10; i <= 500; i += 10) {
 			simulateBetUntilBroke(r,i);
		}
		System.out.println("Try to double your money:");
		for(int i=10; i <= 500; i += 10) {
			simulateTryToDouble(r,i);
		}
		System.out.println("Try to exactly double your money:");
		for(int i=10; i <= 500; i += 10) {
			simulateTryToExactlyDouble(r,i);
		}
   }
	 
	 // take current amount of money and a bet and return new amount of money
	public static int makeOneRedBet(Random r, int startMoney, int bet) {
	 	if(startMoney < bet) { // can't bet more than you have
			bet = startMoney;
		}
		int spin = r.nextInt(WHEEL_SIZE);
//		System.out.println("spin is " + spin);
		if(spin >= RED_MIN && spin <= RED_MAX) {
			return startMoney + bet;
		} else {
			return startMoney - bet;
		}
	 }
	 
	 public static void simulateBetUntilBroke(Random r, int bet) {
	   int spinsSum = 0;
	 	for(int i=1; i <= NUMBER_TRIALS; ++i) {
			int currentMoney = INITIAL_MONEY;
			int spins = 0;
			while(currentMoney > 0) {
				++spins;
	   //  	System.out.println("I have $" + currentMoney);
				currentMoney = makeOneRedBet(r, currentMoney, bet);
			}
		//	System.out.println("I got to play " + count + " times");
			spinsSum += spins;
		}
		double avg = (double)spinsSum / NUMBER_TRIALS;
		System.out.printf("On average, survived %.1f spins when the bet was %d\n", avg, bet);
	 }
	 
	 public static void simulateTryToDouble(Random r, int bet) {
	   int spinsSum = 0;
		int numWins = 0;
	 	for(int i=1; i <= NUMBER_TRIALS; ++i) {
			int currentMoney = INITIAL_MONEY;
			int spins = 0;
			while(currentMoney > 0 && currentMoney < 2*INITIAL_MONEY) {
				++spins;
	   //  	System.out.println("I have $" + currentMoney);
				currentMoney = makeOneRedBet(r, currentMoney, bet);
			}
		//	System.out.println("I got to play " + count + " times");
			spinsSum += spins;
			if(currentMoney > 0) {
				++numWins;
			}
		}
		double avg = (double)spinsSum / NUMBER_TRIALS;
		double winPct = 100.0 * numWins / NUMBER_TRIALS;
		System.out.printf("On average, survived %.1f spins and won %.1f%% when the bet was %d\n", 
								avg, winPct, bet);
	 }
	 
	 public static void simulateTryToExactlyDouble(Random r, int bet) {
	 	int spinsSum = 0;
		int numWins = 0;
	 	for(int i=1; i <= NUMBER_TRIALS; ++i) {
			int currentMoney = INITIAL_MONEY;
			int spins = 0;
			while(currentMoney > 0 && currentMoney < 2*INITIAL_MONEY) {
				++spins;
	   //  	System.out.println("I have $" + currentMoney);
				if(currentMoney + bet <= 2 * INITIAL_MONEY) {
					currentMoney = makeOneRedBet(r, currentMoney, bet);
				} else {
					currentMoney = makeOneRedBet(r, currentMoney, 2*INITIAL_MONEY - currentMoney);
				}
			}
		//	System.out.println("I got to play " + count + " times");
			spinsSum += spins;
			if(currentMoney > 0) {
				++numWins;
			}
		}
		double avg = (double)spinsSum / NUMBER_TRIALS;
		double winPct = 100.0 * numWins / NUMBER_TRIALS;
		System.out.printf("On average, survived %.1f spins and won %.1f%% when the bet was %d\n", 
								avg, winPct, bet);
	 }
}