题解

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

int a[1000005];

int main(){
int w,n,sum = 0;
cin>>w>>n;
for(int i = 0;i < n;i){
cin>>a[i];
}
sort(a,a+n);
int i = 0,j = n - 1;
while(i <= j){
if(a[i] + a[j] <= w){
i,j--;
}
else{
j--;
}
sum++;
}
cout<<sum;
return 0;
}