#include <math.h>
#include <ctype.h>
#include <string>
#include <iostream>
#include <stdlib.h>     /* srand, rand */
#include <time.h>       /* time */
using namespace std;

bool isSquare(double n);
bool isPrime(double n);

int gcd(int a, int b);
int lcm(int a, int b, int gcd);

//1. kiem tra so nguyen
int checkType(double n){
    bool isInt = ((int)(n) == n);
    //Kiem tra sau do luu ket qua vao isN
    bool isN[3] = {isInt, isPrime(n), isSquare(n)};
    string numType[3] = {"nguyen", "nguyen to", "chinh phuong"};

    for(int i = 0; i < 3; i++){
        string neg = (isN[i]) ? "" : " khong phai";
        //them phu dinh vao cau neu N khong phai la so nguyen
        cout << n << neg + " la so " + numType[i]  << "\n";
    }

}

//2. kiem tra uoc boi
int checkCommon(int a, int b){
    int GCD = gcd(a, b);
    printf("\nUoc so lon nhat cua 2 so la: %i", GCD);
    printf("\nBoi so nhat cua 2 so la: %i", lcm(a, b, GCD));
}

//3. tinh tien karaoke
int karaokeProfit(int start, int end){
    //tra ve 0 neu khung gio khong hop le
    if(start < 12 || end > 23) return 0;

    const int price = 50000;
    int total = 0;
    int time = end - start;

    //neu time > 4, giam so tien di 30% voi nhung tieng tiep theo
    if(time >= 4) total = 150000 + (((time - 3)*50000)*0.7);
    else total = time * price;

    //giam them neu bat dau tu 14-17h;
    if(start >= 14 && start <= 17){
        total = (total * 0.9);
    }

    return total;
}

//4. tinh tien dien
void getTienDien(int kw){
    int tong = 0;
    //luu tru so kw su dung va bang gia
    //neu kw > 400, for loop se dung kw de tinh tong
    int kwLookup[7] = {0, 50, 100, 200, 300, 400, kw};
    int giaLookup[6] = {1678, 1734, 2014, 2536, 2834, 2927};

    for (int i = 0; i < 6; i++){
        //kiem tra xem kw trong bac nao. VD: 100 < kw < 200 => bac 2. Cong vao tong dua vao bac.
        if(kw >= kwLookup[i + 1]){
            tong += (kwLookup[i+1] - kwLookup[i]) * giaLookup[i];
        }
        //neu kw < kwLookup => da tim thay bac. Tinh not tong va end for.
        else{
            tong += (kw - kwLookup[i]) * giaLookup[i];
            break;
        }
    }
    printf("\nSo tien phai dong la: %i", tong);
}


//5. doi tien
void getChange(int amount){
    //left la so tien con phai tra.
    int left = amount;
    const int changeLookup[] = {500,200,100,50,20,10,5,2,1};
    //lay do dai cua mang change
    const int length = sizeof(changeLookup)/sizeof(changeLookup[0]);

    printf("\nMenh gia tien doi ra la: ");
    for(int i = 0; left > 0; i++){
        //chi tra ve menh gia nho hon left
        if(left > changeLookup[i]){
            //in ra man hinh tren cung dong so tien phai tra
            printf("%i ", changeLookup[i]);
            left -= changeLookup[i];
            i--;
        }
        //khi left == thi 1 ket thuc chuong trinh
        else if (left == 1){
            printf("1\n");
            return;
        }

    }
}


//6. vay tien
void loanWInterest(int total){
    int current;
    float interest;

    for(int i = 1; i <= 12; i++){
        //so tien con phai tra
        current = total - (total/12) * i;
        //lai xuat 5% cua thang hien tai
        interest = current * 0.05;

        printf("\nSo tien phai tra ky han %i la: %i ", i, (total/12) + (int)interest);
    }
}

//7. vay theo phan tram
void loanUpfront(int percent){
    //gia cua xe,
    int current, total = 500000000;
    float interest;

    //tong so tien phai tra lan dau
    int firstTime = (total / 100) * (100 - percent);
    printf("\nSo tien phai tra lan dau: %i", firstTime);

    total -= firstTime;
    for(int i = 1; i <= 12; i++){
        //so tien con phai tra
        current = total - (total/12) * i;
        //tra them 7.2% lai xuat theo thang
        interest = current * 0.072;
        printf("\nSo tien phai tra ky han %i la: %i", i, total / 12 + (int)interest);
    }
}

void studentClassify(float score, string name){
    if(score < 0 || score > 10){
        printf("\nDiem khong hop le");
        return;
    }
    string hocLuc = "";
    if(score >= 9) hocLuc = "xuat sac";
    else if(score >= 8) hocLuc = "gioi";
    else if(score >= 6.5) hocLuc = "kha";
    else if(score >= 5) hocLuc = "trung binh";
    else if(score >= 3.5) hocLuc = "yeu";
    else hocLuc = "kem";
}


void lottery(int n){
    // khoi tao seed ngau nhien:
    srand (time(NULL));
    int win = rand() % 15 + 1;
}

bool isSquare(double n){
    //lay can bac 2 cua n nhan voi chinh no, tra ve true neu ket qua = n
    int n2 = sqrt(n);
    if (n2 * n2 == n) return true;
    return false;
}

bool isPrime(double n)
{
    if(n < 2) return false;
    // Tim so chia dc cho n tu 2 den n-1. Neu tim dc thi` tra ve false.
    for (int i = 2; i < n; i++){
        if((int)n % i == 0) return false;
    }
    return true;
}

//dung recursion de tim boi so
int gcd(int a, int b)
{
    if (a == 0) return b;
    return gcd(b % a, a);
}
//dung boi so de tim uoc so
int lcm(int a, int b, int gcd){
    return (a * b) / gcd;
}