清点代码库

#include <iostream>
#include <algorithm>
#include <map>
#include <vector>
using namespace std;
map<vector<int>, int> mp;
vector<pair<int,vector<int>>>ans;
int main()
{
    int n, m;
    cin >> n >> m;
    for (int i = 1; i <= n; i ++)
    {
        vector<int>ve;
        for (int j = 1; j <= m; j ++)
        {
            int x;
            scanf("%d", &x);
            ve.push_back(x);
        }
        mp[ve] ++;
    }
    cout << mp.size() << endl;
    for (auto item : mp) ans.push_back({-item.second, item.first});
    //这题最后是先输出最大的，但是sort排序是从小到大，所以这里用了负号
    sort(ans.begin(), ans.end());
    for (auto item : ans) 
    {
        cout << -item.first << ' ';
        for (auto i : item.second) cout << i << ' ';
        cout << endl;
    }
    return 0;
}