Go: ///
// File:  0529.go
// Author: ymiyamoto
//
// Created on Wed Feb 28 20:39:28 2018
//
package main

import (
	"fmt"
	"sort"
)

func max(n, m int) int {
	if n < m {
		return m
	} else {
		return n
	}
}

func main() {
	for {
		var N, M int
		fmt.Scan(&N, &M)
		if N == 0 && M == 0 {
			break
		}

		arr := make([]int, N+1)
		for i := 1; i <= N; i++ {
			fmt.Scan(&arr[i])
		}
		sort.Ints(arr)

		sums := make([]int, len(arr)*len(arr))
		for i := 0; i < len(arr); i++ {
			for j := 0; j < len(arr); j++ {
				sums[i+j] = arr[i] + arr[j]
			}
		}
		sort.Ints(sums)

		m := 0
		for i := 0; i < len(sums); i++ {
			rem := M - sums[i]
			if rem >= 0 {
				index := sort.Search(len(sums), func(i int) bool { return sums[i] > rem }) - 1
				if index >= 0 {
					m = max(m, sums[i]+sums[index])
				}
			}
		}
		fmt.Println(m)
	}
}

C++: #include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int main() {
	int n, m;

	while (cin >> n >> m, n || m) {
		vector<int> point(n + 1);
		vector<int> sum;
		for (int i = 0; i < n; ++i) {
			cin >> point[i];
		}
		for (int i = 0; i < n; ++i) {
			for (int j = i; j < n + 1; ++j) {
				sum.push_back(point[i] + point[j]);
			}
		}
		sort(sum.begin(), sum.end());

		int ans = 0;
		for (int i = 0; i < sum.size(); ++i) {
			int t = m - sum[i];
			cout << "t = " << t << endl;
			vector<int>::iterator it = upper_bound(sum.begin(), sum.end(), t);
			if (it != sum.begin()) {
				ans = max(ans, sum[i] + * (it - 1));
			}
		}
		cout << ans << endl;
	}
}

C++: #include<iostream>
#include<vector>
#include<numeric>
#include<algorithm>
#include<string>
#include<cmath>
#include<set>
#include<map>
#include<stack>
#include<queue>
#define FOR(i,a,b) for(int i=(a);i<(b);i++)
#define REP(i,n) for(int i=0;i<(n);i++)
using namespace std;
typedef long long ll;

int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	
	int N;
	ll M;
	cin >> N >> M;
	if (N == 0 & M == 0) return 0;
	vector<ll> P(N + 1);
	REP(i, N) cin >> P[i];
	P[N] = 0;
	vector<ll> sum((N + 1) * (N + 1));
	REP(i, N + 1)REP(j, N + 1) sum[(N + 1) * i + j] = P[i] + P[j];
	sort(sum.begin(),sum.end());
	ll res = 0;
	REP(i, N + 1)REP(j, N + 1) {
		if (sum[(N + 1) * i + j] <= M) {
			res = max({ res,sum[(N + 1) * i + j],sum[(N + 1) * i + j]
				+ sum[upper_bound(sum.begin(),sum.end(),M - sum[(N + 1) * i + j]) - sum.begin() - 1] });
		}
	}
	cout << res << "\n";

	return 0;
}

C++: //http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2676345#1
//http://judge.u-aizu.ac.jp/onlinejudge/review.jsp?rid=2676345#1
#include <iostream>
#include<cstdlib>
#include<queue>
#include<set>
#include<vector>
#include<string>
#include<algorithm>
#include<stack>
#include<map>
#include<cstdio>
#include<fstream>
#include<cstring>
using namespace std;
#define rep(i,a) for(int i=0;i<a;i++)
#define mp make_pair
#define P pair<int,int>
#define ll __int64

int n,m;
int t[10000];
const int MA=1000000;
int s1[MA],s2[MA];

int ya[4];

int main(){

while(cin>>n>>m,n||m){
rep(i,MA)s1[i]=s2[i]=0;
rep(i,10000)t[i]=0;
for(int i=1;i<=n;i++)cin>>t[i];
for(int i=0;i<=n;i++){
	for(int j=0;j<=n;j++){
		s1[i*(n+1)+j]=t[i]+t[j];
		s2[i*(n+1)+j]=t[i]+t[j];
	}
}
int g=(n+1)*(n+1);

sort(s1,s1+g);
sort(s2,s2+g);

//rep(i,g)cout<<s1[i]<<" ";cout<<endl;

int ans=0;

for(int i=0;i<g;i++){
	int now=s1[i];

	int l=0;
	int r=g-1;
	int mid=(l+r)/2;
	int x=s2[mid];

	for(int i=0;i<100;i++){
		if(x+now==m)break;
		if(x+now>m){
			r=mid;
			mid=(r+l)/2;
			x=s2[mid];
		}
		else{
			l=mid;
			mid=(r+l)/2;
			x=s2[mid];
		}
	}

	//cout<<" "<<x<<" "<<now<<" "<<x+now<<endl;
	if(x+now<=m)
	ans=max(ans,x+now);
}
cout<<ans<<endl;
}
	return 0;
}

C++: #include <iostream>
#include <fstream>
#include <vector>
#include <string>
#include <map>
#include <sstream>
#include <queue>
#include <cstdlib>
#include <algorithm>
#include <iterator>
#include <stack>
#include <list>
using namespace std;
#define INF 100000000
typedef long long int lli;
typedef pair<int,int> P;

int p[1001];
int h[1000*1000+1001];

int main(){
	int n,m,ans;
	while(cin>>n>>m){
		if(n==0&&m==0) break;
		p[0]=0;
		ans=0;
		for(int i=1; i<=n; ++i){
			cin >> p[i];
		}
		for(int i=0; i<=n; ++i){	
			for(int j=0; j<=n; ++j){
				h[i*n+j]=p[i]+p[j];
			}
		}
		sort(h,h+n*n+1);
		/*
		for(int i=0; i<=n*n; ++i){
			cout << h[i] << "\n";
		}
		*/
		for(int i=0; i<=n; ++i){	
			for(int j=0; j<=n; ++j){	
				int tmp=p[i]+p[j];
				int l=0,r=n*n;
				int cnt=0;
				while(1){
					int mid=(r+l)/2;
					if(cnt>=20){
						if(h[mid]+tmp<=m) ans=max(ans,h[mid]+tmp);
						break;
					}
					if(h[mid]+tmp>m){
						r=mid;
					} else if(h[mid]+tmp<m){
						l=mid;
					} else if(h[mid]+tmp==m){
						ans=m;
						break;
					}
					++cnt;
				}
			}
		}
		cout << ans << "\n";
	}
	return 0;
}

C++: 
#include<stdio.h>
#include<stdlib.h>
#include<math.h>

int main()
{
	int ans[4];
	int temp;
	double energy,energy_min,energy_now;
	int M, N;
	int* p;
	int i, j;
	double T=100;
	int ret;
	while (1) {
		scanf("%d%d", &N, &M);
		p = (int*)malloc((N+1) * sizeof(int));
		for (i = 0; i < N; i++) {
			scanf("%d", &p[i]);
		}
		p[N] = 0;
		if (N == M && N == 0) {
			break;
		}
		energy_min = pow(10, 300);
		for (j = 0; j < 4; j++) {
			ans[j] = p[(int)((double)(rand() + 1) / (RAND_MAX + 2)*(N+1))];
		}
		
		for (T = 1000000; T > 100; T--) {
			for (j = 0; j < 4; j++) {
				temp = p[(int)((double)(rand() + 1) / (RAND_MAX + 2)*(N+1))];
				for (j = 0; j < 4; j++) {
					ret = ans[0] + ans[1] + ans[2] + ans[3];
					ret += temp - ans[j];
					energy = M - ret;
					if (M < ret)energy += 100000000;

					if (energy < energy_min) {
						energy_min = energy;
						ans[j] = temp;
					}
					else if ((double)(rand() + 1) / (RAND_MAX + 2) < exp((energy_min - energy) / T*10000)) {
						energy_min = energy;
						ans[j] = temp;
					}
				}

			}
		}
		ret=ans[0]+ +ans[1] + ans[2] + ans[3];
		printf("%d\n", ret);
	}
    return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

#define TEMP_T template<typename T>
TEMP_T void sort(T& v){ sort(v.begin(), v.end()); }
TEMP_T void revs(T& v){ reverse(v.begin(), v.end()); }
TEMP_T void uniq(T& v){ sort(v); v.erase(unique(v.begin(), v.end())); }
TEMP_T void show(T& v, char delim=' ', char end='\n'){ for(int i=0; i<v.size()-1; i++) cout << v[i] << delim; cout << v[v.size()-1] << end; }
TEMP_T T    cums(T& v){ T r; r.push_back(v[0]); for(int i=1; i<v.size(); i++) r.push_back(r[i-1] + v[i]); return r; }
TEMP_T void maxe(T& v, T m){ v = max(v, m); }
TEMP_T void mine(T& v, T m){ v = min(v, m); }

static inline int in(){ int x; scanf("%d", &x); return x; }

int main()
{
  int n, m;
  while (n = in(), m = in()){
    vector<int> p;
    for (int i = 0; i < n; i++){
      p.push_back(in());
    }
    p.push_back(0);
    n++;

    vector<int> pp;
    for (int i = 0; i < n; i++){
      for (int j = 0; j < n; j++){
        pp.push_back(p[i] + p[j]);
      }
    }
    int maxi = 0;
    sort(pp);
    for (int i = 0; i < n; i++){
      for (int j = 0; j < n; j++){
        int s = p[i] + p[j];
        int v = *(upper_bound(pp.begin(), pp.end(), m - s) - 1);
        if (s + v <= m){
          maxe(maxi, s + v);
        }
      }
    }
    printf("%d\n", maxi);
  }

  return 0;
}