Danny_SAA_week9

#include <iostream>

using namespace std;

struct elem {
    int key;
    elem *next;
}*start = nullptr;

void list() {
    if(start) {
        elem *pointer = start;

        while(pointer) {
            cout << pointer->key << "\t";
            pointer = pointer->next;
        }
    } else {
        cout << "\nEmpty";
    }
}

void add_b(int n) {
    elem *pointer = start;
    start = new elem;
    start->key = n;
    start->next = pointer;
}

void add_e(int n) {
    elem *pointer = new elem;

    pointer->key = n;
    pointer->next = nullptr;

    if(start) {
        elem *helper = start;

        while(helper->next != nullptr)
            helper = helper->next;

        helper->next = pointer;
    } else
        start = pointer;
}

void add_bk(int n, int k) {
    elem *pointer = start; // ukazatelqt pointer sochi kum nachaloto na spisuka

    while(pointer->key != k && pointer->next) // vurti, dokato sreshtne k ili ima sledvasht element, ako nqma, shte spre da vurti cikula
        pointer = pointer->next;

    if(pointer->key == k) { // ako kliuchovata stoinost na ukazatelq e ravna na k
        elem *helper = new elem; // suzdavame pomoshten ukazatel

        helper->next = pointer->next; // sledvashtiqt element na pomoshtniqt ukazatel e sledvashtiqt element na pointer ukazatelq
        pointer->next = helper; // sledvashtiqt element na ukazatelq pointer e raven na tekushtiqt ukazatel helper

        // obrushtat se dvete kliuchovi stoinosti, s cel da se dobavi predi tozi element
        helper->key = k;
        pointer->key = n;
    } else
        cout << "K ne e nameren";
}

void add_ak(int n, int k) {
    elem *pointer = start; // ukazatelqt pointer sochi kum nachaloto na spisuka

    while(pointer->key != k && pointer->next) // vurti, dokato sreshtne k ili ima sledvasht element, ako nqma, shte spre da vurti cikula
        pointer = pointer->next; // ukazatelqt pointer se premestva s edin element napred

    if(pointer->key == k) {
        elem *helper = new elem;

        helper->next = pointer->next;
        pointer->next = helper;
        // obrushtat se dvete kliuchovi stoinosti, s cel da se dobavi sled tozi element
        helper->key = n;
        pointer->key = k;
    } else
        cout << "K ne e nameren";
}

void add_sorted(int n) {
    if(start == nullptr || start->key > n) { // ako e purvi element ili ukazatelqt za nachalo ima po-golqma kliuchova stoinost ot n
        add_b(n); // dobavi v nachaloto
    } else {
        elem *pointer = start; // sochi kum nachaloto na spisuka

        while(pointer->key <= n && pointer->next) // dokato ukazatelqt ima kliuchova stoinost po-malka ili ravna na n i ima sledvasht element
            pointer = pointer->next; // premestva se napred kum sledvashtiqt element

        if(pointer->key >= n) // ako ukazatelqt ima kliuchova stoinost po-golqma ili rawna na n
            add_bk(n, pointer->key); // dobavi sled tazi kliuchova stoinost v spisuka
        else // v protiven sluchai
            add_e(n); // dobavi nakraq
    }
}

int del_k(int k) {
    if(start) {
        elem *pointer = start;
        elem *helper = pointer;

        while(pointer->key != k && pointer->next) {// dokato e razlichno ot k i ima sledvasht element
            helper = pointer; // predi da premine kum sledvashtiqt element, zapazva tekushtiqt v nov ukazatel
            pointer = pointer->next; // premestva se napred kum sledvashtiqt element
        }

        if(pointer->key == k) {

            if(start->key == k) // ako purviqt element e raven na k
                start = start->next; // purviqt element se premestva s edin element napred
            else
                helper->next = pointer->next; // preskacha elementa

            delete pointer; // iztriva go
            return 1;
        } else {
            cout << "Nqmam k, nqa kvo da triq";

            return 0;
        }
    } else
        cout << "Prazen spisuk";

    return 0;
}

int main() {

    int k;

    do {
        cout << "\nDigit: ";
        cin >> k;

        if(k) {
            add_sorted(k);
            list();
        }
    } while(k != 0);


    cout << "Vuvedi stoinost, koqto iskash da iztriesh: ";
    cin >> k;

    del_k(k); // iztriva elementa sus stoinost k
    list(); // izvejda spisuka

    return 0;
}