#include "pch.h"
#include <iostream>
#include <string.h>

using namespace std;

typedef struct m {
    int val;
    int index;
    struct m* next;
    struct m* pred;
} *pointer;

pointer M;

void Creat() {
    pointer tmp = NULL;
    cout << "Enter the number: ";
    int n; cin >> n;
    int k = n * 0.9;
    cout << "Enter the integers so that no more than " << k << " are 0:\n";
    for (int i = 0; i < n; i++) {
        if (tmp == NULL) {
            tmp = new m();
            cin >> tmp->val;
            tmp->index = i;
            M = tmp;
        } else {
            tmp->next = new m();
            tmp->next->pred = tmp;
            tmp = tmp->next;
            cin >> tmp->val;
            tmp->index = i;
        }
    }
}

void Compression() {
    pointer tmp = M;
    while (tmp != NULL) {
        if (tmp->val == 0) {
            if (tmp->pred != NULL) {
                tmp->pred->next = tmp->next;
                if (tmp->next != NULL) tmp->next->pred = tmp->pred;
                tmp = tmp->next;
            }
            else {
                M = tmp->next;
                tmp->next->pred = NULL;
                tmp = M;
            }
        }
        else {
            tmp = tmp->next;
        }
    }

    tmp = M;
    cout << "Compressed list:\n";
    while (tmp != NULL) {
        cout << tmp->index << " - " << tmp->val << endl;
        tmp = tmp->next;
    }
}

int Suma() {
    pointer tmp = M;
    int S = 0;
    while (tmp != NULL) {
        S += tmp->val;
        tmp = tmp->next;
    }
    return S;
}

int main()
{
    Creat();
    Compression();
    cout << "The amount is equal: " << Suma();
}