1129. Recommendation System (25)

1129. Recommendation System (25)

#include <iostream>#include <vector>#include <unordered_map>#include <set>#include <algorithm>using namespace std;struct node{    int idx,w;    node(int x,int y):idx(x),w(y){}    bool operator <(const node &nd)const    {        if(w!=nd.w) return w>nd.w;        return idx<nd.idx;    }};int main(){    int n,k;    unordered_map<int,int> cnt;    set<node> mset;    cin>>n>>k;    for(int i=0;i<n;++i)    {        int idx;        cin>>idx;        if(i>0)        {            cout<<idx<<":";            int s=0;            for(auto it=mset.begin();it!=mset.end()&&s!=k;++it,++s)                cout<<" "<<it->idx;            cout<<endl;        }        auto it=mset.find(node(idx,cnt[idx]));        if(it!=mset.end()) mset.erase(it);        mset.insert(node(idx,++cnt[idx]));    }    return 0;}