题解 | 尼科彻斯定理

#include <cmath>
#include <iostream>
#include <vector>
#include <algorithm>
#include <numeric>
using namespace std;

static bool getItems(int n, int num) {
    vector<int> arr(n, 0);
    for (int i = 0; i < n; i++) {
        arr[i] = num + 2 * i;
    }

    if (accumulate(arr.begin(), arr.end(), 0) == pow(n, 3))
        return true;

    return false;
}

int main() {
    int a;
    while (cin >> a) { // 注意 while 处理多个 case

        int sum = a * a * a;

        if (a == 1) {
            cout << a << endl;
        } else {
            int firstNum;
            for (int i = 1; i < sum; i++) {
                if (getItems(a, i)) {
                    firstNum = i;
                    break;
                }
            }

            for (int i = 0; i < a; i++) {
                if (i == a - 1) {
                    cout << (firstNum + 2 * i);
                }     else {

                    cout << (firstNum + 2 * i) << "+";
                }
            }

            cout << endl;

        }



    }
}