RT，刚才的贴发错地方了2333

莫名WA了，30QAQ

// luogu-judger-enable-o2
#include <bits/stdc++.h>
#include <bits/extc++.h>
using namespace std;
using namespace __gnu_pbds;
tree<int,null_type,less<int>,rb_tree_tag,tree_order_statistics_node_update> t;
int m,n,a[200005],i,last=1,u;
int main(){
    scanf("%d%d",&m,&n);
    for (int j=1;j<=m;j++)scanf("%d",&a[j]);
    while(n--){
        scanf("%d",&u);
        for (;last<=u;last++)t.insert(a[last]);
        printf("%d\n",*t.find_by_order(i++));
    }
}