Go: package main

import (
	"bufio"
	"os"
	"strconv"
	"fmt"
)

var scanner = bufio.NewScanner(os.Stdin)

func nextInt() int {
	scanner.Scan()
	i, e := strconv.Atoi(scanner.Text())
	if e != nil {
		panic(e)
	}
	return i
}

func max(x, y int) int {
	if x > y {
		return x
	} else {
		return y
	}
}

func main() {
	sum := make([]int, 5001)
	for {
		n := nextInt()
		if n == 0 {
			break
		}
		for i := 0; i < n; i++ {
			a := nextInt()
			sum[i+1] = sum[i]+a
		}
		ret := sum[1]
		for i := 0; i <= n; i++ {
			for j := i + 1; j <= n; j++ {
				ret = max(ret, sum[j]-sum[i])
			}
		}
		fmt.Println(ret)
	}
}

C++: /*************************************************************************
	> File Name: 1.cpp
	> Author: ralph
	> Mail: 1694487365@qq.com
	> Created Time: 2018年12月26日 星期三 19时30分31秒
 ************************************************************************/

#include<bits/stdc++.h>
using namespace std;
int num[100000],dp[100000];
int main()
{
    int n;
    while(scanf("%d",&n)!=EOF)
    {
        memset(num,0,sizeof(num));
        memset(dp,0,sizeof(dp));
        for(int i=1;i<=n;i++)
        {
            cin>>num[i];
            dp[i]=max(dp[i-1],0)+num[i];
        }
        int maxn=0;
        for(int i=1;i<=n;i++)
        {
            if(dp[i]>maxn) maxn=dp[i];
        }
        cout<<maxn<<endl;
    }
}

C++: #include <iostream>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <vector>

using namespace std;

int main(){
	int n, tmp, max;
	int sum;
	vector<int> v;

	while(cin >> n){
		if(n == 0){
			break;
		}
		v.clear();
		while(n--){
			cin >> tmp;
			v.push_back(tmp);
		}
		max = v[0];
		for(int i = 0; i < v.size(); i++){
			sum = 0;
			for(int j = i; j < v.size(); j++){
				sum += v[j];
				if(sum > max){
					max = sum;
				}
			}
		}
		cout << max << endl;
	}

	return 0;
}

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

using namespace std;
int length=0;
int* sums;

int main(){
  string str="";
  while(1){
  cin>>length;
  if(length==0)break;
  sums=new int[length+1];
  sums[0]=0;
  int s=0;
  for(int i=0;i<length;i++){
    int v=0;
    cin>>v;
    s+=v;
    sums[i+1]=s;
  }
  int max=INT_MIN;
  for(int i=0;i<length+1;i++){
    for(int j=i;j<length+1;j++){
      int diff=sums[j]-sums[i];
      if(diff>max){
        max=diff;
      }
    }
  }
  str+=to_string(max)+"\n";
  }
  cout<<str;
  return 0;
}

C++: #include<iostream>
#include<algorithm>
using namespace std;

int main(){
	int n;
	int sequence[5000];
	int ans;
	int sum;

	while(cin >> n, n){
		for(int i=0; i < n; i++){
			cin >> sequence[i];
		}
		ans = sequence[0];

		for(int i=0; i < n; i++){
			sum = 0;
			for(int j=i; j < n; j++){
				sum += sequence[j];
				ans = max(sum, ans);
			}
		}
		cout << ans << endl;
	}
}

C++: #include <iostream>
#include <cstdio>
using namespace std;

long long a[5000];

int main(){
	int n;
	while(cin >> n && n){
		long long ans = 1e9;
		for(int i = 0 ; i < n ; i++) cin >> a[i] , ans = max(ans, a[i]);
		long long sub = 0;
		for(int i = 0 ; i < n ; i++){
			sub += a[i];
			if( sub < 0 ){
				sub = 0;
			}else{
				ans = max(ans,sub);
			}
		}
		cout << ans << endl;
	}
}

C++: #include<iostream>
#include<string>
#include<vector>
#include<algorithm>
#include<functional>
using namespace std;
int main(){
	int n;
	while(cin>>n,n){
		int sum=0,a[5001],ans=-999999999;
		vector<int>anss(0);
		for(int i=0;i<n;i++)cin>>a[i];
		for(int i=0;i<n;i++){
			sum=0;
			for(int j=i;j<n;j++){
				sum+=a[j];
				ans=max(sum,ans);
				//anss.push_back(sum);
			}
		}
		cout<<ans<<endl;
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
using namespace std;

int main(){
    int n;
    while(cin >> n, n){
        vector<int> a(n,0);
        for(int i=0; i<n; ++i){
            cin >> a[i];
        }
        // ????????£?¶??????????????????§??£?¶???????dp??¨?????????
        vector<int> dp(n,0);
        dp[0] = a[0];
        int max = 0;
        for(int i=0; i<n; ++i){
            if(dp[i-1]>0){
                dp[i] = dp[i-1] + a[i];
            } else {
                dp[i] = a[i];
            }
            if(max<dp[i]){
                max = dp[i];
            }
        }
        cout << max << endl;
    }
}

C++: #include<iostream>
#include<cstdio>
using namespace std;

int main(){
  int i,j,n,max,sum,a[5001];
  while(1){
    cin>>n;
    if(n==0)break;
    for(i=0;i<n;i++){
      cin>>a[i];
    }
    max=a[0];
    for(i=0;i<n;i++){ 
      sum=0;
      for(j=i;j<n;j++){
	sum+=a[j];
	if(max<sum)max=sum;	
      }
    }
    cout<<max<<endl;
  }
  return 0;
}

C++: #include <iostream>
using namespace std;
int main(){
	for (;;){
		int a,goukei=0,max=-999999999,b;
		cin>>a;
		if (a==0)break;
		int data[a+1]={0};
		for (int A=1;A<=a;A++){
			cin>>data[A];
			if (max<data[A])max=data[A];
			goukei+=data[A];
			data[A]=goukei;
			if (max<data[A])max=data[A];
		}max=-999999999;
		for (int A=3;A<a;A++){
			b=A-2;
			for (int B=b;B>0;B--){
				goukei=0;
				goukei=data[A]-data[B];
				if (goukei>max) max=goukei;
			}
		}
		cout<<max<<endl;
	}
	return 0;
}

C++: #include<iostream>
#include<string>
#include<cstdio>
#include<algorithm>
#include<stack>
#include<queue>
#include<vector>
#include<cmath>
#include<utility>
#include<set>
#include<complex>
#include<map>
#define vi vector<int>
#define vvi vector<vector<int> >
#define ll long long int
#define vl vector<ll>
#define vvl vector<vector<ll>>
#define vb vector<bool>
#define vc vector<char>
#define vs vector<string>
#define ld long double
#define INF 1e9
#define EPS 0.0000000001
#define rep(i,n) for(int i=0;i<n;i++)
#define loop(i,s,n) for(int i=s;i<n;i++)
#define CC puts("-------ok--------");
#define all(in) in.begin(), in.end()
using namespace std;
typedef pair<int, int> pii;
#define MAX 99999999
int main(){
    int n;
    while(cin>>n,n){
        vi v(n+1,0);
        rep(i,n)cin>>v[i];
        ll ans=0;
        for(int i=0;i<n;i++){
            ll temp=0;
            for(int j=i;j<n;j++){
            for(int k=i; k<=j;k++)temp+=v[k];
            ans=max(ans,temp);
                temp=0;
            }
        }
        cout<<ans<<endl;
    }
}

C++: //まともに使い方を理解していないくせにincludeしまくる人間のクズ
#include <cstdio>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <cctype>
#include <vector>
#include <algorithm>
#include <stack>
#include <queue>
#include <list>
#include <set>
#include <map>
#include <bitset>


//using namespace stdしないと表記がめんどくさいからね、仕方ないね
using namespace std;

//可読性を上げるためのdefineが仇となる典型的パターン
#define rep(n) for(int i = 0; i < x; i++)

//ローカル変数とグローバル変数は使い分けよう！
stack<short> x, y;
unsigned long int ans, array[5000];
short i, n;
//関数って楽しいよね！（魔王スマイル）

void solve(unsigned long int sum, short i){
    if(ans < sum) ans = sum;
    if(i == n) return;
    solve(sum + array[i], i + 1);
    solve(0, i + 1);
    return;
}

int main(){
    while(true){
        scanf("%lld", &n);
        if(n == 0) return 0;
        ans = 0;
        for(i = 0; i < n; i++) scanf("%lld", &array[i]);
        solve(0, 0);
        printf("%lld\n", ans);
    }
}

C++: //0022 Maximum Sum Sequece

//2<=n<=5000ÂÌñ©çA×Ú·éÌaÌÅålð¦æ
//È¨AÌlÍ-10`10ÌÍÍÅ é
//KÉâÁ½ç°i(1¨n-1){i*(n-i)}ñÅ]TÅlÞ©
//Æè ¦¸Ag¤ñÌÉV½ÉÁíÁ½àÌð«µÄAÁ¦éàÌðø­ûjÅ¢¢©


#include<iostream>
#include<algorithm>
#include<numeric>
#include<climits>
using namespace std;

int main(void)
{
	const int N = 5000;
	int n;
	while(cin >> n, n)
	{
		int i, j;
		int a[N];
		int sum, max_sum = INT_MIN;

		for(i = 0; i < n; i++)
			cin >> a[i];

		//iÂÌðg¤
		for(i = 1; i <= n; i++)
		{
			//Ü¸ÍAÜÆÜÁÄg¤ªÌaðvZµÄ¨­
			sum = accumulate(a, a+i, 0);
			max_sum = max(sum, max_sum);

			for(j = 0; j+i < n; j++)
			{
				//ÌÂðg¢Ü·
				sum -= a[j];
				sum += a[j+i];
				max_sum = max(max_sum, sum);
			}
		}

		cout << max_sum << endl;
	}
	return 0;
}