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<stdio.h>
#include<algorithm>

#define rep(i,j) for(int i=0;i<(j);i++)
#define reps(i,j,k) for(int i=j;i<=k;i++)

const int s=1001*501;
int dp[s];
int n,m,ans,p[1001],cnt;
int *po;
using namespace std;


int main(){
	for(;;){
		scanf("%d%d",&n,&m);
		if(n==0&&m==0)break;
		p[0]=0;
		rep(i,n)scanf("%d",p+i+1);
		cnt=0;
		rep(i,n+1){
			for(int j=0;j<=i;j++){
				dp[cnt++]=p[i]+p[j];
			}
		}
		ans=0;
		sort(dp,dp+cnt);
		rep(i,cnt){
			po = upper_bound(dp,dp+cnt,m-dp[i]);
			if(po!=dp)ans=max(ans,dp[i]+*(po-1));
		}
	//	rep(i,cnt)printf("%3d",dp[i]);
		printf("%d\n",ans);
	}
	return 0;
}

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

#define MAX_N (1000)
#define MAX_M (2 * 1e8)

using namespace std;

int field[MAX_N];
int fld[MAX_N * MAX_N];

int N,M;

int ans;

int bin_search(int tar,int *s,int *e){
	int result;
	int width = e - s;
	while(true){
		width = e - s;
		if(width <= 1){
			result = *s;
			break;
		}

		if(*(s + (width / 2)) <= tar){
			s = s + (width / 2);
		}
		else{
			e = s + (width / 2) - 1;
		}
	}
	
	return result;
}

void solve(){
	for(int i = 0;i <= N;i++){
		for(int j = 0;j <= N;j++){
			fld[(N + 1) * i + j] = field[i] + field[j];
		}
	}

	sort(fld,fld + (N + 1) * (N + 1));

	int rest;
	int sample;
	for(int i = 0;i <= N;i++){
		for(int j = 0;j <= N;j++){
			rest = M - (field[i] + field[j]);
			if(rest < 0) break;
			sample = bin_search(rest,fld,fld + (N + 1) * (N + 1));
			ans = max(ans,field[i] + field[j] + sample);
		}
	}

	return ;
}

int main(){

	while(true){
		scanf("%d%d",&N,&M);
		if(N == 0 && M == 0) break;
		for(int i = 1;i <= N;i++){	//fiest element is 0;
			scanf("%d",field + i);
		}

		solve();

		printf("%d\n",ans);

	}

	return 0;
}

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

#define MAX_N 1001

using namespace std;

int main(void){
	while( 1 ){
		int n, m;
		int V[MAX_N] = {0,};
		int D[MAX_N][4] = {{0,},};
		int Max = 0;

		cin >> n >> m;

		if( n == 0 && m == 0 ){
			break;
		}

		for(int i = 0; i < n; i++){
			cin >> V[i];
		}
		V[n] = 0;
		n++;

		sort(V, V + n);
		reverse(V, V + n);

		for(int i = 0; i < n; i++){
			for(int j = 0; j < 4; j++){
				D[i][j] = V[i];
				if( j > 0 ){
					int thisMax = 0;
					for(int k = 0; k <= i; k++){
						int tmp = D[i][j] + D[k][j - 1];
						thisMax = max(thisMax, tmp > m ? 0 : tmp);
					}
					if( thisMax > D[i][j] ){
						D[i][j] = thisMax;
					}
				}
			}
		}

		for(int i = 0; i < n; i++){
			for(int j = 0; j < 4; j++){
				//cout << D[i][j] << ' ';
				if( D[i][j] <= m ){
					if( Max < D[i][j] ){
						Max = D[i][j];
					}
				}
			}
			//cout << '\n';
		}

		cout << Max << '\n';
	}
	return 0;
}

C++: #include <vector>
#include <list>
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <deque>
#include <algorithm>
#include <utility>
#include <functional>
#include <sstream>
#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cctype>
#include <string>
#include <cstring>
#include <ctime>
#include <climits>
#include <cassert>
using namespace std;
inline int toInt(string s) {int v; istringstream sin(s);sin>>v;return v;}
template<class T> inline string toString(T x) {ostringstream sout;sout<<x;return sout.str();}
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef vector<string> vs;
typedef pair<int, int> pii;
typedef long long ll;
#define ALL(a) (a).begin(),(a).end()
#define RALL(a) (a).rbegin(),(a).rend()
#define EXIST(s,e) ((s).find(e)!=(s).end())
#define FOR(i,a,b) for(int i=(a);i<(b);++i)
#define REP(i,n) FOR(i,0,n)
#define EACH(t,i,c) for(t::iterator i=(c).begin(); i!=(c).end(); ++i)
const double EPS = 1e-10;
const double PI  = acos(-1.0);

typedef vector<ll> vl;
int main(){
	ll n,m;
	while(cin>>n>>m,n|m){
		vl a(n);
		REP(i,n){
			cin>>a[i];
		}
		a.push_back(0);
		vl ds;
		REP(i,a.size()){
			FOR(j,i,a.size()){
				ds.push_back(a[i]+a[j]);
			}
		}
		sort(ALL(ds));
		ll ans=0;
		REP(i,a.size()){
			REP(j,a.size()){
				ll sum=a[i]+a[j];
				if(sum>m){continue;}
				vl::iterator it=upper_bound(ALL(ds),m-sum);
				if(it==ds.begin())continue;
				ll total=sum+*(it-1);
				if(total>m)total=0;
				ans=max(ans,total);
			}
		}
		cout<<ans<<endl;
	}
}

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

using namespace std;

int main() {
	int n[1000], m[1000], p[10][1000],ans=0, i = 0;
	vector<int> v;
	while (cin >> n[i] >> m[i]) {
		if (n[i] == 0)break;
		for (int j = 0; j < n[i]; j++)cin >> p[i][j];
		i++;
	}
	for (int k = 0; k < i; k++) {
		ans = 0;
		v = vector<int>(1,0);
		for (int a = 0; a < n[k]; a++) {
			v.push_back(p[k][a]);
			for (int b = 0; b < n[k]; b++)
				v.push_back(p[k][a] + p[k][b]);
		}
		sort(v.begin(), v.end());
		for (int j = 0; j < v.size(); j++) {
			if (v[j] > m[k])break;
			decltype(v)::iterator itr= upper_bound(v.begin(), v.end(), m[k]-v[j]);
			itr--;
			ans = max(ans, v[j] + *itr);
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include <iostream>
#include <string.h>
#include <algorithm>
#include <set>
#include <cstdio>
#include <vector>
using namespace std;

int main() {
	int N, M;
	while(cin >> N >> M && (N || M)){
		int  P[1001] = {0}, ans = 0;
		for(int i = 0; i < N; ++i){
			scanf("%d", &P[i]);
		}
		set<int> darts;
		for(int i = 0; i <= N; ++i){
			for(int j = 0; j <= N; ++j){
				if(P[i] + P[j] <= M)
				darts.insert(darts.end(), P[i] + P[j]);
			}
		}
		vector<int> v(darts.begin(), darts.end());
		for(unsigned int i = 0; i < v.size(); ++i){
			if(v[i] > M)
				continue;
			set<int>::iterator it = darts.lower_bound(M - v[i]);
			if(it == darts.end())
				--it;
			if(*it > M - v[i])
				--it;
					
			ans = max(ans, v[i] + *it);
		}
		/*for(int i = 0; i <= N; ++i){
			for(int j = 0; j <= N; ++j){
				if(P[i] + P[j] > M)
					continue;
				set<int>::iterator it = darts.lower_bound(M - (P[i] + P[j]));
				if(it == darts.end())
					--it;
				if(*it > M - (P[i] + P[j]))
					--it;
					
				ans = max(ans, P[i] + P[j] + *it);
			}
		}*/
		cout << ans << endl;
	}
	return 0;
}