/* * Bai 1 */ public static HashMap<Integer, Integer> tanSo(int[][] array){ HashMap<Integer,Integer> result = new HashMap<>(); for(int i=0; i<array.length; i++){ for(int j=0; j<array[0].length; j++){ if(result.containsKey(array[i][j])){ int newValue = result.get(array[i][j])+1; result.put(array[i][j],newValue); }else{ result.put(array[i][j], 1); } } } return result; } /* * Bai 2 * 2 loi sai * iter.next()/2 !=0 * phan else cung phai thuc hien next neu ko iter se ko tiep tuc di tiep */ public static boolean kiemTraBoiSo2(Iterator<Integer> iter){ boolean result = false; while(iter.hasNext()){ int num = iter.next(); if((num % 2) == 0){ result = true; } } return result; }

package Bai3; import java.util.HashMap; public class ThiSinh implements Comparable<ThiSinh>{ private String maTS; private String hoTen; private int tongDiem; private HashMap<DotThi, Integer> diemChiTiet = new HashMap<>(); public ThiSinh(String maTS, String hoTen) { this.maTS = maTS; this.hoTen = hoTen; this.tongDiem = tongDiem(); } public int tongDiem(){ int result = 0; if(!diemChiTiet.isEmpty()){ for(Integer diem : diemChiTiet.values()){ result += diem; } } return result; } public void themDiem(DotThi dt, int diem){ this.diemChiTiet.put(dt, diem); } @Override public int compareTo(ThiSinh another) { return tongDiem - another.tongDiem; } package Bai3; public class DotThi { private String ten; private String maDT; public DotThi(String ten, String maDT) { super(); this.ten = ten; this.maDT = maDT; } package Bai3;

import java.util.TreeSet; public class MasterCheft { private int year; private String national; private TreeSet<ThiSinh> dsThiSinh; public MasterCheft(int year, String national) { this.year = year; this.national = national; } public void addThiSinh(ThiSinh ts){ this.dsThiSinh.add(ts); } public void removeThiSinh(ThiSinh ts){ this.dsThiSinh.remove(ts); } package Bai4; import java.util.HashMap; import java.util.StringTokenizer; public class CaesarCoding { private final char[] mangChuCai = new char[]{'A','B','C','D','E','F','G','H','J','K', 'L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'}; private HashMap<Character,Character> taoBangChuCai_MaHoa(int doDich){ HashMap<Character,Character> result = new HashMap<>(); int length = mangChuCai.length; for(int i=0; i< length; i++){ int viTri = i+doDich; if(viTri < length){ result.put(mangChuCai[i], mangChuCai[viTri]); }else{ result.put(mangChuCai[i], mangChuCai[length - viTri]); } } return result; } public HashMap<Character,Character> hoaDoi(HashMap<Character,Character> bangCode){ HashMap<Character,Character> result = new HashMap<>(); for(Character key : bangCode.keySet()){ result.put(bangCode.get(key), key); } return result; }

public String process(HashMap<Character,Character> codingTable,String text){ String result =""; StringTokenizer tokens = new StringTokenizer(text," ?./()*"); while(tokens.hasMoreElements()){ String word = tokens.nextToken(); String codedWord =""; for(int i=0; i<word.length(); i++){ codedWord += codingTable.get(word.charAt(i)); } result += codedWord +" "; } return result; } public String maHoa(int doDich,String text){ HashMap<Character,Character> codingTable = this.taoBangChuCai_MaHoa(doDich); return this.process(codingTable, text); } public String giaiMa(int doDich,String text){ HashMap<Character,Character> codingTable = this.taoBangChuCai_MaHoa(doDich); return this.process(this.hoaDoi(codingTable), text); }