stl的应用 注意不要用unordered_map 因为它不能判断vector

有坑 cin过不来~~ 请换成scanf

#include<iostream>
#include<cstring>
#include<cstdio>
#include<algorithm>
#include<vector>
#include<map>
#define x first
#define y second
using namespace std;
int n,m;

map<vector<int>,int> ma;
vector<pair<int,vector<int>>> v;
int main(){
    scanf("%d%d", &n, &m);
    for(int i=1;i<=n;i++){
        vector<int> line;
        for(int i=0;i<m;i++){
            int x;
            scanf("%d", &x);
            line.push_back(x);
        }

        ma[line]++;
    }

    for(auto &p:ma){
        v.push_back({-p.y,p.x});
    }

    sort(v.begin(),v.end());
    cout<<v.size()<<endl;
    for(auto &t:v){
        cout<<t.x*(-1)<<" ";
        for(auto x:t.y){
            cout<<x<<" ";
        }
        cout<<endl;
    }
    return 0;

}