3842589_ac_422ms_3496k.java

北大大牛代码 1240道题的原代码 超级权威

//package poj.p1560;

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

public class Main {

	private String[] table = new String[26];
	private String elements;

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		new Main().run();
	}

	private void run() {
		Scanner in = new Scanner(System.in);
		int n;

		label: while (true) {
			n = in.nextInt();
			if (n == 0) {
				break;
			}
			elements = in.next();
			System.out.print("S = {");
			for (int i = 0; i < n; i++) {
				System.out.print(elements.charAt(i));
				if (i != n - 1) {
					System.out.print(",");
				} else {
					System.out.println("}");
				}
			}
			System.out.println(" #|" + elements);
			System.out.print(" -+");
			for (int i = 0; i < n; i++) {
				System.out.print("-");
			}
			System.out.println();
			for (int i = 0; i < n; i++) {
				table[i] = in.next();
				System.out.println(" " + elements.charAt(i) + "|" + table[i]);
			}
			System.out.println();
			String tmp = sort();
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < n; j++) {
					char ch = getTableEntry(tmp.charAt(i), tmp.charAt(j));
					if (elements.indexOf(ch) == -1) {
						System.out.println("NOT A SEMIGROUP: " + tmp.charAt(i)
								+ "#" + tmp.charAt(j) + " = " + ch
								+ "  WHICH IS NOT AN ELEMENT OF THE SET");
						end();
						continue label;
					}
				}
			}
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < n; j++) {
					for (int k = 0; k < n; k++) {
						char ch1 = getTableEntry(tmp.charAt(i), tmp.charAt(j));
						ch1 = getTableEntry(ch1, tmp.charAt(k));
						char ch2 = getTableEntry(tmp.charAt(j), tmp.charAt(k));
						ch2 = getTableEntry(tmp.charAt(i), ch2);
						if (ch1 != ch2) {
							System.out.println("NOT A SEMIGROUP: ("
									+ tmp.charAt(i) + "#" + tmp.charAt(j)
									+ ")#" + tmp.charAt(k)
									+ " IS NOT EQUAL TO " + tmp.charAt(i)
									+ "#(" + tmp.charAt(j) + "#"
									+ tmp.charAt(k) + ")");
							end();
							continue label;
						}
					}
				}
			}
			for (int i = 0; i < n; i++) {
				for (int j = 0; j < n; j++) {
					char ch1 = getTableEntry(tmp.charAt(i), tmp.charAt(j));
					char ch2 = getTableEntry(tmp.charAt(j), tmp.charAt(i));
					if (ch1 != ch2) {
						System.out.println("SEMIGROUP BUT NOT COMMUTATIVE  ("
								+ tmp.charAt(i) + "#" + tmp.charAt(j)
								+ " IS NOT EQUAL TO " + tmp.charAt(j) + "#"
								+ tmp.charAt(i) + ")");
						end();
						continue label;
					}
				}
			}
			System.out.println("COMMUTATIVE SEMIGROUP");
			end();
		}
	}

	private char getTableEntry(char ch1, char ch2) {
		// TODO Auto-generated method stub
		return table[elements.indexOf(ch1)].charAt(elements.indexOf(ch2));
	}

	private String sort() {
		// TODO Auto-generated method stub
		char[] charArray = elements.toCharArray();
		Arrays.sort(charArray);
		return new String(charArray);
	}

	private void end() {
		System.out.println("------------------------------\n");
	}

}