二分，简单易懂

#include <bits/stdc++.h>
using namespace std;

const int N = 1e5+10;

int n,m;
int a[N];

int main(){
    cin >> n >> m;
    for(int i = 0;i < n;i++){
        cin >> a[i];
    }
    sort(a,a+n);
    while(m--){
        int w;
        cin >> w;
        int l = 0,r = n;
        while(l < r){
            int mid = (l+r)/2;
            if(a[mid]<=w){
                l = mid+1;
            }else{
                r = mid;
            }
        }
        cout << l << endl;
    }
    return 0;
}