public class Diem {
    private String tenHocPhan;
    private int soTinChi;
    private double chuyenCan, giuaKy, cuoiKy;

    public Diem(String tenHocPhan, int soTinChi) {
        this.tenHocPhan = tenHocPhan;
        setSoTinChi(soTinChi);
    }

    public void setSoTinChi(int tc) {
        if (tc >= 1 && tc <= 4) this.soTinChi = tc;
    }

    public void setChuyenCan(double d) { if (d >= 0 && d <= 10) chuyenCan = d; }
    public void setGiuaKy(double d)    { if (d >= 0 && d <= 10) giuaKy = d; }
    public void setCuoiKy(double d)    { if (d >= 0 && d <= 10) cuoiKy = d; }

    public double tinhDiem() {
        return chuyenCan * 0.1 + giuaKy * 0.2 + cuoiKy * 0.7;
    }

    @Override
    public String toString() {
        double d = Math.round(tinhDiem() * 100) / 100.0;
        return tenHocPhan + " (" + soTinChi + " TC): " + d;
    }

public class SinhVien {
    private String hoTen;
    private Diem dm1, dm2;

    public SinhVien(String hoTen, Diem dm1, Diem dm2) {
        this.hoTen = hoTen;
        this.dm1 = dm1;
        this.dm2 = dm2;
    }

    public double tinhDTB() {
        int tc1 = dm1.getSoTinChi(), tc2 = dm2.getSoTinChi();
        if (tc1 + tc2 == 0) return 0;                 // chan chia 0
        return (dm1.tinhDiem() * tc1 + dm2.tinhDiem() * tc2) / (tc1 + tc2);
    }
}

// ===== Diem.java =====
public class Diem {
    private String tenHocPhan;
    private int soTinChi;
    private double chuyenCan, giuaKy, cuoiKy;

    public Diem(String tenHocPhan, int soTinChi) {
        this.tenHocPhan = tenHocPhan;
        setSoTinChi(soTinChi);
    }

    public String getTenHocPhan() { return tenHocPhan; }
    public int getSoTinChi()      { return soTinChi; }

    public void setSoTinChi(int tc) {
        if (tc >= 1 && tc <= 4) this.soTinChi = tc;
    }

    public double getChuyenCan() { return chuyenCan; }
    public void setChuyenCan(double d) { if (d >= 0 && d <= 10) chuyenCan = d; }

    public double getGiuaKy() { return giuaKy; }
    public void setGiuaKy(double d) { if (d >= 0 && d <= 10) giuaKy = d; }

    public double getCuoiKy() { return cuoiKy; }
    public void setCuoiKy(double d) { if (d >= 0 && d <= 10) cuoiKy = d; }

    public double tinhDiem() {
        return chuyenCan * 0.1 + giuaKy * 0.2 + cuoiKy * 0.7;
    }

    @Override
    public String toString() {
        double d = Math.round(tinhDiem() * 100) / 100.0;
        return tenHocPhan + " (" + soTinChi + " TC): " + d;
    }
}

// ===== SinhVien.java =====
public class SinhVien {
    private String hoTen;
    private Diem dm1, dm2;

    public SinhVien(String hoTen, Diem dm1, Diem dm2) {
        this.hoTen = hoTen;
        this.dm1 = dm1;
        this.dm2 = dm2;
    }

    public String getHoTen() { return hoTen; }
    public Diem getDm1()     { return dm1; }
    public Diem getDm2()     { return dm2; }

    public double tinhDTB() {
        int tc1 = dm1.getSoTinChi();
        int tc2 = dm2.getSoTinChi();
        if (tc1 + tc2 == 0) return 0;
        return (dm1.tinhDiem() * tc1 + dm2.tinhDiem() * tc2) / (tc1 + tc2);
    }

    @Override
    public String toString() {
        double dtb = Math.round(tinhDTB() * 100) / 100.0;
        return hoTen + " | " + dm1 + " | " + dm2 + " | DTB = " + dtb;
    }
}

// ===== QuanLySV.java =====
public class QuanLySV {
    static Diem taoDiem(String ten, int tc, double cc, double gk, double ck) {
        Diem d = new Diem(ten, tc);
        d.setChuyenCan(cc);
        d.setGiuaKy(gk);
        d.setCuoiKy(ck);
        return d;
    }

    public static void main(String[] args) {
        Diem d1 = taoDiem("Lap trinh Java", 3, 9, 8, 7);
        Diem d2 = taoDiem("Toan roi rac",   2, 6, 7, 8);
        Diem d3 = taoDiem("Co so du lieu",  3, 10, 9, 8);
        Diem d4 = taoDiem("Ky nang mem",    2, 5, 6, 5);
        Diem d5 = taoDiem("Cau truc du lieu", 4, 7, 7, 7);
        Diem d6 = taoDiem("Thuc tap",       1, 8, 9, 10);

        SinhVien[] ds = new SinhVien[3];
        ds[0] = new SinhVien("Nguyen Van An",   d1, d2);
        ds[1] = new SinhVien("Tran Thi Binh",   d3, d4);
        ds[2] = new SinhVien("Le Van Chi",      d5, d6);

        for (int i = 0; i < ds.length; i++) {
            System.out.println(ds[i]);
        }

        // kiem tra validation: gan diem sai
        d1.setCuoiKy(15);
        System.out.println("Cuoi ky sau khi gan 15: " + d1.getCuoiKy());
    }
}

public boolean themHP(Diem d) {
    if (d == null || soHP >= dsHP.length) return false;
    dsHP[soHP] = d;
    soHP++;
    return true;
}

public double tinhDTB() {
    double tongDiem = 0;
    int tongTC = 0;
    for (int i = 0; i < soHP; i++) {
        tongDiem += dsHP[i].tinhDiem() * dsHP[i].getSoTinChi();
        tongTC   += dsHP[i].getSoTinChi();
    }
    return (tongTC == 0) ? 0 : tongDiem / tongTC;
}

// ===== SinhVienMoRong.java =====
public class SinhVienMoRong {
    private String hoTen;
    private Diem[] dsHP;
    private int soHP;

    public SinhVienMoRong(String hoTen, int soMonToiDa) {
        this.hoTen = hoTen;
        this.dsHP = new Diem[soMonToiDa];
        this.soHP = 0;
    }

    public String getHoTen() { return hoTen; }
    public int getSoHP()     { return soHP; }

    public boolean themHP(Diem d) {
        if (d == null || soHP >= dsHP.length) return false;
        dsHP[soHP] = d;
        soHP++;
        return true;
    }

    public double tinhDTB() {
        double tongDiem = 0;
        int tongTC = 0;
        for (int i = 0; i < soHP; i++) {
            tongDiem += dsHP[i].tinhDiem() * dsHP[i].getSoTinChi();
            tongTC   += dsHP[i].getSoTinChi();
        }
        return (tongTC == 0) ? 0 : tongDiem / tongTC;
    }

    @Override
    public String toString() {
        double dtb = Math.round(tinhDTB() * 100) / 100.0;
        String s = hoTen + " (" + soHP + " hoc phan, DTB = " + dtb + ")\n";
        for (int i = 0; i < soHP; i++) {
            s += "  " + dsHP[i] + "\n";
        }
        return s;
    }
}

// ===== QuanLySV2.java =====
public class QuanLySV2 {
    public static void main(String[] args) {
        SinhVienMoRong sv = new SinhVienMoRong("Nguyen Van An", 10);

        Diem d1 = new Diem("Lap trinh Java", 3);
        d1.setChuyenCan(9); d1.setGiuaKy(8); d1.setCuoiKy(7);

        Diem d2 = new Diem("Toan roi rac", 2);
        d2.setChuyenCan(6); d2.setGiuaKy(7); d2.setCuoiKy(8);

        Diem d3 = new Diem("Co so du lieu", 3);
        d3.setChuyenCan(10); d3.setGiuaKy(9); d3.setCuoiKy(8);

        System.out.println("Them 1: " + sv.themHP(d1));
        System.out.println("Them 2: " + sv.themHP(d2));
        System.out.println("Them 3: " + sv.themHP(d3));
        System.out.println("Them null: " + sv.themHP(null));

        System.out.println(sv);
    }
}

public double khoangCach(DiemToaDo p) {
    double dx = this.x - p.x;
    double dy = this.y - p.y;
    return Math.sqrt(dx * dx + dy * dy);
}

@Override
public String toString() { return "(" + x + ", " + y + ")"; }

public double chieuDai()  { return Math.abs(d2.getX() - d1.getX()); }
public double chieuRong() { return Math.abs(d2.getY() - d1.getY()); }

public double chuVi()    { return 2 * (chieuDai() + chieuRong()); }
public double dienTich() { return chieuDai() * chieuRong(); }

// ===== DiemToaDo.java =====
public class DiemToaDo {
    private double x, y;

    public DiemToaDo(double x, double y) {
        this.x = x;
        this.y = y;
    }

    public double getX() { return x; }
    public double getY() { return y; }

    public double khoangCach(DiemToaDo p) {
        double dx = this.x - p.x;
        double dy = this.y - p.y;
        return Math.sqrt(dx * dx + dy * dy);
    }

    @Override
    public String toString() { return "(" + x + ", " + y + ")"; }
}

// ===== HCN.java =====
public class HCN {
    private DiemToaDo d1;   // goc tren trai
    private DiemToaDo d2;   // goc duoi phai

    public HCN(DiemToaDo d1, DiemToaDo d2) {
        this.d1 = d1;
        this.d2 = d2;
    }

    public DiemToaDo getD1() { return d1; }
    public DiemToaDo getD2() { return d2; }

    public double chieuDai()  { return Math.abs(d2.getX() - d1.getX()); }
    public double chieuRong() { return Math.abs(d2.getY() - d1.getY()); }

    public double chuVi()    { return 2 * (chieuDai() + chieuRong()); }
    public double dienTich() { return chieuDai() * chieuRong(); }

    @Override
    public String toString() {
        return "[" + d1 + ", " + d2 + "]";
    }
}

// ===== QuanLyHCN.java =====
public class QuanLyHCN {
    public static void main(String[] args) {
        HCN[] ds = new HCN[5];
        ds[0] = new HCN(new DiemToaDo(0, 4), new DiemToaDo(3, 0));
        ds[1] = new HCN(new DiemToaDo(0, 3), new DiemToaDo(2, 0));
        ds[2] = new HCN(new DiemToaDo(1, 5), new DiemToaDo(6, 1));
        ds[3] = new HCN(new DiemToaDo(0, 2), new DiemToaDo(2, 0));
        ds[4] = new HCN(new DiemToaDo(0, 6), new DiemToaDo(1, 0));

        System.out.println("Danh sach ban dau:");
        for (int i = 0; i < ds.length; i++) {
            System.out.println(ds[i] + " chu vi = " + ds[i].chuVi()
                             + ", dien tich = " + ds[i].dienTich());
        }

        // sap xep theo dien tich tang dan
        for (int i = 0; i < ds.length - 1; i++) {
            for (int j = 0; j < ds.length - 1 - i; j++) {
                if (ds[j].dienTich() > ds[j + 1].dienTich()) {
                    HCN tmp = ds[j];
                    ds[j] = ds[j + 1];
                    ds[j + 1] = tmp;
                }
            }
        }

        System.out.println("Sau khi sap xep theo dien tich:");
        for (int i = 0; i < ds.length; i++) {
            System.out.println(ds[i] + " dien tich = " + ds[i].dienTich());
        }
    }
}