Problem:
Score: 400 points

Problem Statement

To become a millionaire, M-kun has decided to make money by trading in the next N days. Currently, he has 1000 yen and no stocks - only one kind of stock is issued in the country where he lives.

He is famous across the country for his ability to foresee the future. He already knows that the price of one stock in the next N days will be as follows:

A_1 yen on the 1-st day, A_2 yen on the 2-nd day, ..., A_N yen on the N-th day.

In the i-th day, M-kun can make the following trade any number of times (possibly zero), within the amount of money and stocks that he has at the time.

Buy stock: Pay A_i yen and receive one stock.

Sell stock: Sell one stock for A_i yen.

What is the maximum possible amount of money that M-kun can have in the end by trading optimally?

Constraints

2 \leq N \leq 80

100 \leq A_i \leq 200

All values in input are integers.

Input

Input is given from Standard Input in the following format:

N
A_1 A_2 \cdots A_N

Output

Print the maximum possible amount of money that M-kun can have in the end, as an integer.

Sample Input 1

7
100 130 130 130 115 115 150

Sample Output 1

1685

In this sample input, M-kun has seven days of trading. One way to have 1685 yen in the end is as follows:

Initially, he has 1000 yen and no stocks.

Day 1: Buy 10 stocks for 1000 yen. Now he has 0 yen.

Day 2: Sell 7 stocks for 910 yen. Now he has 910 yen.

Day 3: Sell 3 stocks for 390 yen. Now he has 1300 yen.

Day 4: Do nothing.

Day 5: Buy 1 stock for 115 yen. Now he has 1185 yen.

Day 6: Buy 10 stocks for 1150 yen. Now he has 35 yen.

Day 7: Sell 11 stocks for 1650 yen. Now he has 1685 yen.

There is no way to have 1686 yen or more in the end, so the answer is 1685.

Sample Input 2

6
200 180 160 140 120 100

Sample Output 2

1000

In this sample input, it is optimal to do nothing throughout the six days, after which we will have 1000 yen.

Sample Input 3

2
157 193

Sample Output 3

1216

In this sample input, it is optimal to buy 6 stocks in Day 1 and sell them in Day 2, after which we will have 1216 yen.

Solution in Java (OpenJDK 11.0.6) (judge verdict: Accepted)

import java.util.Arrays;
import java.util.Scanner;

public class Main {

	public static String Y = "Yes";
	public static String N = "No";
	public static long MOD = (long) (Math.pow(10, 9) + 7);
	public static Scanner sc = new Scanner(System.in);

	static long kabu;
	static long kane;

	public static void main(String[] args) {

		int n = ni();
		//		int n = 80;
		int a[] = new int[n];
		for (int i = 0; i < n; i++) {
			a[i] = ni();
		}
		//		for (int i = 0; i < n; i += 2) {
		//			a[i] = 100;
		//		}
		//		for (int i = 1; i < n; i += 2) {
		//			a[i] = 200;
		//		}

		kabu = 0l;
		kane = 1000l;

		for (int i = 0; i < n - 1; i++) {
			if (a[i] < a[i + 1]) {
				buy(kane, a[i]);
			} else {
				uru(a[i]);
			}
			//			debug();
			//			out(kane);
			//			out(kabu);
			//			debug();
		}

		uru(a[n - 1]);

		out(kane);

	}

	static void buy(long shojimoney, long kabumoney) {
		long pluskabu = shojimoney / kabumoney;
		kabu += pluskabu;
		kane -= pluskabu * kabumoney;
	}

	static void uru(long kabumoney) {
		kane += kabu * kabumoney;
		kabu = 0;
	}

	static int popcount(int n) {
		return Long.bitCount(n);
		//		for (;;) {
		//			n /= 2;
		//			debug("popcount:" + n);
		//			count++;
		//			if (n == 0) {
		//				out("popcountres=" + count);
		//				break;
		//
		//			}
		//		}
	}

	static int f(int n) {
		int count = 0;
		for (;;) {
			n = n % popcount(n);
			count++;
			if (n == 0) {
				break;
			}
		}
		return count;
	}

	/*
	 * 以下メソッド集
	 */
	static char[][] same(char[][] c, int h, int w) {
		char[][] a = new char[h][w];
		for (int i = 0; i < h; i++) {
			for (int j = 0; j < w; j++) {
				a[i][j] = c[i][j];
			}
		}
		return a;

	}

	static int countkuro(char[][] c) {
		int count = 0;
		for (char[] cc : c) {
			for (char ccc : cc) {
				if ('#' == ccc) {
					count++;
				}
			}
		}
		return count;
	}

	static double[] sort(double[] r) {
		Arrays.sort(r);
		return r;
	}

	static void debug() {
		out("---");
	}

	static void debug(long a) {
		out("-------");
		out(a);
		out("-------");
	}

	static void debug(String a) {
		out("-------");
		out(a);
		out("-------");
	}

	static long[] sort(long[] n) {
		Arrays.sort(n);
		return n;
	}

	static int ketasuu(int n) {
		String str = "" + n;
		return str.length();
	}

	static int account(String str) {
		String target = "1";
		int count = 0;
		int len = str.length();
		for (int i = 0; i < len - 1; i++) {
			if (target.equals(str.substring(i, i + target.length()))) {
				count++;
			}
		}
		return count;
	}

	static int ni() {
		return sc.nextInt();
	}

	static long nl() {
		return sc.nextLong();
	}

	static double nd() {
		return sc.nextDouble();
	}

	static String n() {
		return sc.next();
	}

	static char[] nc() {
		return sc.next().toCharArray();
	}

	static int kaijo(int n) {
		if (n == 0 || n == 1) {
			return 1;
		} else {
			return n * kaijo(n - 1);
		}
	}

	static int fib(int n) {
		return (n == 1 || n == 0) ? n : fib(n - 2) + fib(n - 1);
	}

	static long lcm(long m, long n) {

		return m * n / gcd(m, n);
	}

	static int lcm(int m, int n) {

		return m * n / gcd(m, n);
	}

	static long gcd(long a, long b) {
		return (b == 0) ? a : gcd(b, a % b);
	}

	static int gcd(int a, int b) {
		return (b == 0) ? a : gcd(b, a % b);
	}

	static void out(String info) {
		System.out.println(info);
	}

	static void out(int info) {
		System.out.println(info);
	}

	static void out(double info) {
		System.out.println(info);
	}

	static void out(long info) {
		System.out.println(info);
	}

	static void out(char info) {
		System.out.println(info);
	}

	static void out(Object obj) {
		System.out.println(obj.toString());
	}

	static void outn(String info) {
		System.out.print(info);
	}

	static void outn(int info) {
		System.out.print(info);
	}

	static void outn(double info) {
		System.out.print(info);
	}

	static void outn(long info) {
		System.out.print(info);
	}

	static void outn(char info) {
		System.out.print(info);
	}

	static double max(double d, double e) {
		return Math.max(d, e);
	}

	static long max(long a, long b) {
		return Math.max(a, b);
	}

	static long min(long d, long e) {
		return Math.min(d, e);
	}

	static int min(int a, int b) {
		return (int) Math.min(a, b);
	}
}

class XY {
	int h;
	int c;

	XY(int h, int c) {
		this.h = h;
		this.c = c;
	}
}