UVA – 1189 – Find The Multiple

Can be solved also using BFS reducing the number of states to MOD only :).

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;
import java.util.StringTokenizer;

public class Multiples {
	static int MOD;
	static int[][] dp;
	static int[][] choice;

	public static int go(int i, int mod) {
		if (mod == 0)
			return i;
		else if (i > 100)
			return 1 << 25;
		else if (dp[i][mod] != -1)
			return dp[i][mod];
		int a = go(i + 1, (mod * 10 + 1) % MOD);
		int b = go(i + 1, (mod * 10 + 0) % MOD);
		if (a <= b)
			choice[i][mod] = 1;
		else
			choice[i][mod] = 0;
		return dp[i][mod] = (a < b) ? a : b;
	}

	public static void main(String[] args) throws Exception {
		InputReader in = new InputReader(System.in);
		while (true) {
			MOD = in.nextInt();
			if (MOD == 0)
				break;
			dp = new int[101][MOD];
			choice = new int[101][MOD];
			for (int i = 0; i < dp.length; i++)
				Arrays.fill(dp[i], -1);
			go(1, 1 % MOD);
			String res = "1";
			int i = 1;
			int m = 1 % MOD;
			while (m != 0) {
				res = res + choice[i][m];
				m = (m * 10 + choice[i][m]) % MOD;
				i++;
			}
			System.out.println(res);
		}
	}

	static class InputReader {
		private BufferedReader reader;
		private StringTokenizer tokenizer;

		public InputReader(InputStream stream) {
			reader = new BufferedReader(new InputStreamReader(stream));
			tokenizer = null;
		}

		public String next() {
			while (tokenizer == null || !tokenizer.hasMoreTokens()) {
				try {
					tokenizer = new StringTokenizer(reader.readLine());
				} catch (IOException e) {
					throw new RuntimeException(e);
				}
			}
			return tokenizer.nextToken();
		}

		public int nextInt() {
			return Integer.parseInt(next());
		}
	}
}