cf Round552E（思维）

#include<cstdio>
#include<cstring>
#include<iostream>
#include<algorithm>
#include<vector>
#include<map>
#include<queue>
#include<set>
using namespace std;
const int maxn = 2e5 + 10;
int n, k;


int main()
{
    cin >> n >> k;
    vector<pair<int, int> > a(n);
    for(int i = 0; i < n; i++)
    {
        cin >> a[i].first;                    
        a[i].second = i;
    }
    sort(a.rbegin(), a.rend());
    //for(int i = 0; i < n; i++)
        //cout << a[i].first << " " << a[i].second << endl;
    queue<int> q;
    for(int i = 0; i < n; i++)
        q.push(a[i].second);

    set<int> idx;
    for(int i = 0; i < n; i++)
    {
        idx.insert(i);
    }
    string ans(n, '0');
    int who = 0;
    while(!idx.empty())
    {
        while(!idx.count(q.front()))            //已经被选走，往后走
        {
            q.pop();
        }
        int pos = q.front();                    //
        q.pop();

        vector<int> add;
        set<int>::iterator it = idx.find(pos);
        for(int i = 0; i <= k; i++)
        {
            add.push_back(*it);
            if(it == idx.begin())   break;
            --it;
        }
        it = idx.find(pos);
        it++;
        for(int i = 0; i < k; i++)
        {
            if(it == idx.end()) break;
            add.push_back(*it);
            ++it;
        }
        for(int i = 0; i < add.size(); i++)
        {
            int t = add[i];
            idx.erase(t);
            ans[t] = '1' + who;
        }
        who ^= 1;
        //cout << "now who is " << who << endl;
    }
    cout << ans << endl;

    return 0;
}