C++ 代码：计算队列中元素差为 200 倍数的方案数

#include <iostream>
#include <vector>

using namespace std;

int main() {
    int n;
    cin >> n;
    vector<int> nums(n);
    for (int i = 0; i < n; i++) {
        cin >> nums[i];
    }

    vector<int> count(200, 0);
    for (int i = 0; i < n; i++) {
        int remainder = nums[i] % 200;
        count[remainder]++;
    }

    long long ans = 0;
    for (int i = 0; i < 200; i++) {
        int cnt = count[i];
        ans += 1LL * cnt * (cnt - 1) / 2;
    }

    cout << ans << endl;

    return 0;
}