三个数可分等差数列

#include <iostream>
#include <vector>

using namespace std;

void printGroups(vector<int>& sequence1, vector<int>& sequence2, vector<int>& sequence3, vector<int>& sequence4) {
    cout << "Group 1: ";
    for (int i = 0; i < sequence1.size(); i++) {
        cout << sequence1[i] << " ";
    }
    cout << endl;

    cout << "Group 2: ";
    for (int i = 0; i < sequence2.size(); i++) {
        cout << sequence2[i] << " ";
    }
    cout << endl;

    cout << "Group 3: ";
    for (int i = 0; i < sequence3.size(); i++) {
        cout << sequence3[i] << " ";
    }
    cout << endl;

    cout << "Group 4: ";
    for (int i = 0; i < sequence4.size(); i++) {
        cout << sequence4[i] << " ";
    }
    cout << endl;
}

void countWays(vector<int>& numbers, vector<int>& removed, vector<int>& sequence1, vector<int>& sequence2, vector<int>& sequence3, vector<int>& sequence4, int index, int& count) {
    if (sequence1.size() == 4 && sequence2.size() == 4 && sequence3.size() == 4 && sequence4.size() == 4) {
        count++;
        printGroups(sequence1, sequence2, sequence3, sequence4);
        cout << "Removed numbers: ";
        for (int i = 0; i < removed.size(); i++) {
            cout << removed[i] << " ";
        }
        cout << endl;
        cout << endl;
        return;
    }

    if (index >= numbers.size()) {
        return;
    }

    // 尝试将当前数添加到第一个等差数列中
    if (sequence1.size() < 4) {
        if (sequence1.size() < 2 || numbers[index] - sequence1[sequence1.size() - 1] == sequence1[1] - sequence1[0]) {
            sequence1.push_back(numbers[index]);
            countWays(numbers, removed, sequence1, sequence2, sequence3, sequence4, index + 1, count);
            sequence1.pop_back();
        }
    }

    // 尝试将当前数添加到第二个等差数列中
    if (sequence2.size() < 4) {
        if (sequence2.size() < 2 || numbers[index] - sequence2[sequence2.size() - 1] == sequence2[1] - sequence2[0]) {
            sequence2.push_back(numbers[index]);
            countWays(numbers, removed, sequence1, sequence2, sequence3, sequence4, index + 1, count);
            sequence2.pop_back();
        }
    }

    // 尝试将当前数添加到第三个等差数列中
    if (sequence3.size() < 4) {
        if (sequence3.size() < 2 || numbers[index] - sequence3[sequence3.size() - 1] == sequence3[1] - sequence3[0]) {
            sequence3.push_back(numbers[index]);
            countWays(numbers, removed, sequence1, sequence2, sequence3, sequence4, index + 1, count);
            sequence3.pop_back();
        }
    }

    // 尝试将当前数添加到第四个等差数列中
    if (sequence4.size() < 4) {
        if (sequence4.size() < 2 || numbers[index] - sequence4[sequence4.size() - 1] == sequence4[1] - sequence4[0]) {
            sequence4.push_back(numbers[index]);
            countWays(numbers, removed, sequence1, sequence2, sequence3, sequence4, index + 1, count);
            sequence4.pop_back();
        }
    }

    // 将当前数添加到已移除的数中
    removed.push_back(numbers[index]);

    // 不将当前数添加到任何一个等差数列中
    countWays(numbers, removed, sequence1, sequence2, sequence3, sequence4, index + 1, count);

    // 将当前数从已移除的数中移除
    removed.pop_back();
}

int main() {
    vector<int> numbers = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19};
    vector<int> removed, sequence1, sequence2, sequence3, sequence4;
    int count = 0;

    countWays(numbers, removed, sequence1, sequence2, sequence3, sequence4, 0, count);

    cout << "Number of ways: " << count << endl;

    return 0;
}