Replace repeating numbers

/**
 * The program replace repeating numbers to two values - value and count of repeating
 *
 *
 * Source array: 84 84 84 101 115 116 32 79 79 79 79 79 79 80 80 80 80 80
 *
 * From array: 84 84 84 101 115 116 32 79 79 79 79 79 79 80 80 80 80 80
 * Remove from position 0 (value 84) to position 2 (value 84)
 * 84 -2 101 115 116 32 79 79 79 79 79 79 80 80 80 80 80
 *
 * From array: 84 -2 101 115 116 32 79 79 79 79 79 79 80 80 80 80 80
 * Remove from position 6 (value 79) to position 11 (value 79)
 * 84 -2 101 115 116 32 79 -5 80 80 80 80 80
 *
 * From array: 84 -2 101 115 116 32 79 -5 80 80 80 80 80
 * Remove from position 8 (value 80) to position 12 (value 80)
 * 84 -2 101 115 116 32 79 -5 80 -4

 * Result array: 84 -2 101 115 116 32 79 -5 80 -4
 * Replacements:
 * 79 was replaced 5 time(s)
 * 80 was replaced 4 time(s)
 * 84 was replaced 2 time(s)
 */

#include <vector>
#include <iostream>
#include <map>

using std::vector;
using std::map;
using std::cout;
using std::endl;

map<int, int> trim_array(vector<int>& arr) {
    map<int, int> replacements;

    for (size_t i = 0; i < arr.size() - 1; ++i) {
        size_t from = i; // С  какого индекса удалять
        size_t to   = i; // До какого индекса удалять

        // Ищем до какого индекса удалять
        while (to + 1 < arr.size() && arr[from] == arr[to + 1]) to++;

        if (from != to) {
            cout << "From array: ";
            for (auto value : arr) cout << value << " ";
            cout << endl << "Remove from position " << from << " (value " << arr[from] << ") to position " << to << " (value " << arr[to] << ")" << endl;

            const int replaceValue = arr[from];
            const int replaceCount = to - from;

            // Заменяли ли мы это число
            if (replacements.find(replaceValue) != replacements.end()) replacements[replaceValue] += replaceCount;
            else replacements[replaceValue] = replaceCount;

            arr.erase(arr.begin() + from, arr.begin() + to);
            arr.insert(arr.begin() + from + 1, -replaceCount);
            i++;

            for (auto value : arr) cout << value << " ";
            cout << endl << endl;
        }
    }
    return replacements;
}

int main() {
    vector<int> arr{ 84, 84, 84, 101, 115, 116, 32, 79, 79, 79, 79, 79, 79, 80, 80, 80, 80, 80 };

    cout << "Source array: ";
    for (auto value : arr) cout << value << " ";
    cout << endl;

    auto replacements = trim_array(arr);

    cout << "Result array: ";
    for (auto value : arr) cout << value << " ";
    cout << endl;

    cout << "Replacements:" << endl;
    for (const auto& replacement : replacements) {
        cout << replacement.first << " was replaced " << replacement.second << " time(s)" << endl;
    }

    system("pause");
    return 0;
}