package test2;

import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;

public class Utility2C {

	private Utility2C() {
		
	}
	
	/**
	 * Returns the last character in the argument string.
	 * 
	 * @param s a string
	 * @return the last character in s
	 * @pre. s is not empty
	 */
	public static char last(String s) {
		return s.charAt(s.length() - 1);
	}
	
	/**
	 * Returns true if the string t is equal to the string s
	 * in reverse, and false otherwise. For example,
	 * 
	 * <pre>
	 * Utility2C.areReversed("abcd", "dcba")
	 * </pre>
	 * 
	 * <p>
	 * returns true.
	 * 
	 * @param s a non-null string
	 * @param t a non-null string
	 * @return true if t is equal to the string s
	 * in reverse, and false otherwise
	 * @throws IllegalArgumentException if the length of
	 * s is not equal to the length of t
	 */
	public static boolean areReversed(String s, String t) {
		if (s.length() != t.length()) {
			throw new IllegalArgumentException("");
		}
		for (int i = 0; i < s.length(); i++) {
			if (s.charAt(i) != t.charAt(t.length() - i - 1)) {
				return false;
			}
		}
		return true;
	}
	
	
	/**
	 * Returns a list of the characters that appear more than once
	 * in the string s. The returned list contains no duplicate
	 * characters. For example:
	 * 
	 * <pre>
	 * Utility2C.repeatedChars("hi")        returns the empty list
	 * Utility2C.repeatedChars("EECS")      returns the list ['E']
	 * Utility2C.repeatedChars("EECS2030")  returns the list ['E', '0']
	 * </pre>
	 *  
	 * @param s a non-null string
	 * @return a list of the characters that appear more than once
	 * in the string s
	 */
	public static List<Character> repeatedChars(String s) {
		List<Character> result = new ArrayList<Character>();
		Set<Character> t = new HashSet<Character>();
		for (int i = 0; i < s.length(); i++) {
			char c = s.charAt(i);
			if (t.contains(c) && !result.contains(c)) {
				result.add(c);
			}
			t.add(c);
		}
		return result;
	}
	
	public static void main(String[] args) {
		int x = Integer.MAX_VALUE;
		int y = Integer.MIN_VALUE;
		System.out.println("" + (x - y));
	}
	
}