#include<bits/stdc++.h>
using namespace std;
int dp[1<<21],v[1<<21],a[21];//当前状态下最小电梯次数，及当前状态下剩余的空间
int main(){
    memset(dp,0x3f,sizeof(dp));
    int n,w;
    cin>>n>>w;
    for(int i=1;i<=n;i++){
        cin>>a[i];
    }
    dp[0]=1;
    for(int i=0;i<=(1<<n)-1;i++){
        for(int j=1;j<=n;j++){
            if(i&1<<(j-1)){
                continue;
            }
            else{
                if(v[i]+a[j]<=w){
                    if(dp[i|1<<(j-1)]<dp[i]){
                        continue;
                    }
                    if(dp[i|1<<(j-1)]==dp[i]){
                        v[i|1<<(j-1)]=min(v[i|1<<(j-1)],v[i]+a[j]);
                    }
                    else{
                        dp[i|1<<(j-1)]=dp[i];
                        v[i|1<<(j-1)]=v[i]+a[j];
                    }
                }else{
                    if(dp[i|1<<(j-1)]<dp[i]+1){
                        continue;
                    }
                    if(dp[i|1<<(j-1)]==dp[i]+1){
                        v[i|1<<(j-1)]=min(v[i|1<<(j-1)],v[i]+a[j]-w);//这里
                    }
                    else{
                        dp[i|1<<(j-1)]=dp[i]+1;
                        v[i|1<<(j-1)]=v[i]+a[j]-w;//还有这里
                    }
                }
            }
            //cout<<"i="<<i<<" j="<<j<<" dp="<<dp[i|1<<(j-1)]<<" v="<<v[i|1<<(j-1)]<<endl;
        }
    }
    cout<<dp[(1<<n)-1]<<endl;
    return 0;
}

如果你像我这样可以把奶牛切成两半装进电梯的话你就会喜提100pts+被hack