1109. Group Photo (25)

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>
using namespace std;
struct node {
    string name;
    int len;
    bool operator<(const node b)const {
        return len < b.len || (len == b.len && name >b.name);
    }
};
void change(vector<node> &x)
{
    int mid = x.size() / 2;
    vector<node> te(x.rbegin(),x.rend());
    int cnt = 0;
    x[mid] = te[cnt++];
    for (int t = 1;t < x.size() - mid;t++)
    {
        x[mid - t] = te[cnt++];
        x[mid + t] = te[cnt++];
    }
    if (cnt == x.size() - 1) x[0] = te[cnt++];

}
int main()
{
    int N, K;
    cin >> N >> K;
    vector<node> all(N);
    vector<vector<node>> re(K);
    for (int t = 0;t < N;t++)
        cin >> all[t].name >> all[t].len;
    sort(all.begin(), all.end());
    int n = N / K;
    for (int t = 0;t < K - 1;t++)
        re[t].assign(all.begin()+t*n,all.begin()+(t+1)*n);
    re[K - 1].assign(all.begin() + (K - 1)*n, all.end());

    for (auto &x : re)
        change(x);
    for (auto it = re.rbegin();it != re.rend();it++)
    {
        cout << (*it)[0].name;
        for (unsigned int t = 1;t < (*it).size();t++)
            cout << " " << (*it)[t].name;
        cout << endl;

    }
}