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

import (
	"fmt"
	"sort"
)

func max(n, m int64) int64 {
	if n < m {
		return m
	} else {
		return n
	}
}

func main() {
	for {
		var N int
		var M int64
		fmt.Scan(&N, &M)
		if N == 0 && M == 0 {
			break
		}

		arr := make([]int64, N+1)
		for i := 1; i <= N; i++ {
			fmt.Scan(&arr[i])
		}
		sort.Slice(arr, func(i, j int) bool { return arr[i] < arr[j] })

		sums := make([]int64, len(arr)*len(arr))
		for i := 0; i < len(arr); i++ {
			for j := 0; j < len(arr); j++ {
				sums[i*len(arr)+j] = arr[i] + arr[j]
			}
		}

		sort.Slice(sums, func(i, j int) bool { return sums[i] < sums[j] })

		var m int64 = 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 <string>
#include <sstream>
#include <vector>
#include <algorithm>
#include <numeric>
#include <set>
#include <map>
#include <queue>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <cctype>
#include <cassert>
#include <cmath>
#include <limits>
#include <functional>

#define REP(i,n) for(int i=0;i<n;i++)
#define FOR(i,m,n) for(int i=m;i<n;i++)
#define FORR(i,m,n) for(int i=m;i>=n;i--)
#define pb(x) push_back(x) 
#define SORT(x) sort((x).begin(),(x).end())
#define INF 999999999

using namespace std;

#define int long long

signed main(){
	int n, m;
	cin >> n >> m;
	vector<int> p(n);
	REP(i, n){
		cin >> p[i];
	}
	p.push_back(0);
	sort(p.begin(), p.end());
	n++;
	
	vector<int> v;
	REP(i, n){
		REP(j, n){
			v.push_back(p[i]+p[j]);
		}
	}
	SORT(v);
	
	int l=0, r=v.size()-1, ans=0;
	for(; l<r; l++){
		if(v[l]+v[r]>m) r--;
		ans=max(ans, v[l]+v[r]);
	}
	
	cout << ans << endl;
}

C++: #include<cstdio>
#include<algorithm>
using namespace std;
int f[210000000];
int main(void)
{
	int a,s,d[1000],high,low,ba,naka,nokori,kore,g,h,i,j,z,x,c,v;
	while(1){
		kore=0;
		scanf("%d %d",&a,&s);
		if(a==0&&s==0)
			break;
		d[0]=0;
		for(i=1;i<=a;i++){
			scanf("%d",&d[i]);
		}
		g=0;
		for(i=0;i<=a;i++){
			for(j=i;j<=a;j++){
				f[g]=d[i]+d[j];
				g++;
			}
		}
		sort(f,f+g);
		/*for(i=0;i<g;i++)
			printf("%d\n",f[i]);*/
		
		for(i=0;i<g;i++){
			v=0;
			low=0;
			high=g-1;
			nokori=s-f[i];
		//	printf("%d %d\n",i,nokori);
			if(nokori>=0){
				while(1){
					if(low>high)
						break;
					naka=(low+high)/2;
				//	printf("%d = %d %d %d %d %d\n",i,f[high],f[naka],f[low],f[i],nokori);
					if(nokori>f[naka]){
						low=naka+1;
					//	printf("%d %d %d low\n",i,nokori,f[naka]);
					}
					if(nokori<f[naka]){
						high=naka-1;
					//	printf("%d %d %d high\n",i,nokori,f[naka]);
					}
					if(nokori==f[naka]){
						ba=f[naka];
						v=1;
						break;
					}
				}
				if(v==0)
					ba=f[low-1];
				//printf("%d\n",f[i]+ba);
				if(kore<f[i]+ba){
					kore=f[i]+ba;
				//	printf("   %d\n",kore);
				}
			}
		}
		printf("%d\n",kore);
	}
	return 0;
}

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

// Shrotening
#define fst first
#define snd second
#define pb push_back
#define mp std::make_pair

// Loop
#define FOR(i,a,b) for(auto i=(a);i<(b);++i)
#define RFOR(i,a,b) for(auto i=(a);i>=(b);--i)

#define REP(i,a) for(long i=0;i<(a);++i)
#define RREP(i,a) for(long i=(a);i>=0;--i)

#define EACH(i,a) for(auto (i)=(a).begin(),_END=(a).end();i!=_END;++i)
#define REACH(i,a) for(auto (i)=(a).rbegin(),_END=(a).rend();i!=_END;++i)

//Algorithm
#define ALL(a) (a).begin(), a.end()
#define RALL(a) (a).rbegin(), a.rend()
#define EXIST(a,x) ((a).find(x)!=(a).end())
#define SORT(a) std::sort((a).begin(), (a).end())
#define UNIQUE(a) std::sort((a).begin(), a.end()), a.erase(std::unique((a).begin(), a.end()), a.end());
#define SUM(a) std::accumulate((a).begin(), (a).end(), 0);

//Setting
#define OPT std::cin.tie(0);std::ios::sync_with_stdio(false);

//debug message
bool debug = true;
#define MSG(s)   if(debug){std::cout << s << std::endl;}
#define DEBUG(x) if(debug){std::cout << "debug(" << #x << "): " << x << std::endl;}

//alias
typedef long long LL;
typedef std::vector<char> VC;
typedef std::vector<int>  VI;
typedef std::vector<long> VL;
typedef std::vector<long long> VLL;

typedef std::vector< VC > VC2;
typedef std::vector< VI > VI2;
typedef std::vector< VL > VL2;
typedef std::vector< VLL > VLL2;

typedef std::pair<int,int> PII;


int N, M;
VI P(1000);
VI sum(1000000);

int main() {
    while(std::cin >> N >> M) {
        if(N == 0 && M == 0) break;
        REP(i, N) {
            std::cin >> P[i];
        }

        int cnt = 0;
        for(int i=0; i<=N; ++i) {
            for(int j=0; j<=N; ++j) {
                int s= 0;
                s += (i < N ? P[i] : 0);
                s += (j < N ? P[j] : 0);
                if(s > M) continue;
                sum[cnt++] = s;
            }
        }
        std::sort(sum.begin(), sum.begin() + cnt);



        int ans = 0;
        for(int i=0; i<cnt; ++i) {
            int v2 = *(std::upper_bound(sum.begin(), sum.begin()+cnt, M - sum[i]) - 1);
            ans = std::max(ans, sum[i] + v2);
        }
        std::cout << ans << std::endl;
    }
}

C++: #include <cstdio>
#include <algorithm>
#include <set>
#include <vector>
using namespace std;

int n, m;
int p[1000];
int ans;
vector<int> v;

void solve(){
	ans = 0;
	v.clear();
	v.push_back(0);
	for(int i = 0; i < n; i++){
		scanf("%d", &p[i]);
		if(p[i] <= m) v.push_back(p[i]);
	}
	for(int i = 0; i < n; i++){
		for(int j = 0; j < n; j++){
			if(p[i]+p[j] <= m) v.push_back(p[i]+p[j]);
		}
	}
	sort(v.begin(),v.end());
	int j = v.size()-1;
	for(int i = 0; i < v.size(); i++){
		while(true){
			if(v[i]+v[j] <= m){
				ans = max(ans,v[i]+v[j]);
				break;
			}
			j--;
		}
	}
	printf("%d\n", ans);
}

int main(){
	while(scanf("%d%d", &n, &m),n||m) solve();
}

C++: #include <bits/stdc++.h>
#define FOR(i,n) for(int i=0;i<(int)(n);i++)
#define FORR(i,m,n) for(int i=(int)(m);i<(int)(n);i++)
#define pb(a) push_back(a)
#define mp(x,y) make_pair(x,y)
#define ZERO(a) memset(a,0,sizeof(a))
#define len(a) sizeof(a)
#define ll long long
#define pii pair<int,int>
#define INF 1<<29
#define MAX 1010
using namespace std;

int p[MAX];

void solve(){
 int n,m,ind;
 for(;;){
  cin>>n>>m;
  if(!n) break;
  int ma=0;
  vector<int> v;
  FOR(i,n){
   cin>>p[i];
   v.pb(p[i]);
  }
  FOR(i,n){
   FORR(j,i,n){
    v.pb(p[i]+p[j]);
   }
  }
  sort(v.begin(),v.end());
  v.erase(unique(v.begin(),v.end()),v.end());
  ind=upper_bound(v.begin(),v.end(),m)-v.begin()-1;
  if(ind>=0) ma=v[ind];
  FOR(i,v.size()){
   ind=upper_bound(v.begin(),v.end(),m-v[i])-v.begin()-1;
   if(ind>=0) ma=max(ma,v[i]+v[ind]);
  }
  cout<<ma<<endl;
 }
}

int main(){
 solve();
 return 0;
}

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

constexpr int MAX_N = 1001;

int n, m;
int p[MAX_N];
std::vector<int> sums;

int main() {
	while (1) {
		std::cin >> n >> m;
		if (n + m == 0)
			break;
		sums.clear();
		for (int i = 0; i < n; ++i)
			std::cin >> p[i];
		++n;
		p[n - 1] = 0;
		for (int i = 0; i < n; ++i) {
			for (int j = i; j < n; ++j)
				sums.push_back(p[i] + p[j]);
		}
		std::sort(sums.begin(), sums.end());
		sums.erase(std::unique(sums.begin(), sums.end()), sums.end());
		int res = 0;
		for (int i = 0; i < n; ++i) {
			for (int j = 0; j < n; ++j) {
				auto it = std::upper_bound(sums.begin(), sums.end(), m - p[i] - p[j]);
				if (it != sums.begin()) {
					--it;
					res = std::max(res, (*it) + p[i] + p[j]);
				}
			}
		}
		std::cout << res << std::endl;
	}
	return 0;
}