输入上万的题目 用scanf不要用cin。 我写的也是暴力O(n^2),AC了
#include <iostream>
#include <vector>
#include <algorithm>
#include <unordered_map>
#include <map>
#include <set>

using namespace std;

class Solution{
public:
    int getKMul(vector<int>& v, int k){
        int sum;
        int mxlen = 0;
        for (int i=0; i<v.size(); i++) {
            sum = 0;
            for (int j=i; j<v.size(); j++) {
                sum += v[j];
                if (sum % k == 0) {
                    mxlen = max(j-i+1, mxlen);
                }
            }
            if (mxlen >= v.size()-i) {
                break;
            }
        }
        return mxlen;
    }
};

int main(){
    int n;
    cin>>n;
    vector<int> v;
    int x;
    for (int i=0; i<n; i++) {
        scanf("%d",&x);
        v.push_back(x);
    }
    int k;
    cin>>k;
    Solution s;
    cout<<s.getKMul(v, k)<<endl;
}