Go: package main

import (
        "fmt"
)

func main() {
        for {
                var n int
                _, err := fmt.Scanf("%d", &n)
                if err != nil || n == 0 {
                        break
                }

                var sum [5001]int

                for i := 1; i <= n; i++ {
                        fmt.Scanf("%d", &(sum[i]))
                        if i > 1 {
                                sum[i] += sum[i-1]
                        }
                }

                max_sum := sum[1]
                for i := 1; i <= n; i++ {
                        for j := 0; j < i; j++ {
                                if max_sum < sum[i] - sum[j] {
                                        max_sum = sum[i] - sum[j]
                                }
                        }
                }
                fmt.Printf("%d\n", max_sum)
        }
}

C++: // 0022.cpp : コンソール アプリケーションのエントリ ポイントを定義します。
//

#include<stdio.h>
#include <algorithm>
#include <cassert>
#include <cctype>
#include <climits>
#include <cmath>
#include <complex>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iostream>
#include <iterator>
#include <list>
#include <map>     
#include <numeric>
#include <queue>
#include <set>
#include <sstream>
#include <iomanip>
#include <stack>
#include <string>
#include <vector>
using namespace std;
#define ll long long
#define ld long double
#define roop(a,t) for(ll a=0;a<t;a++) 
ll main()
{
	cin.tie(0);
	ios::sync_with_stdio(false);
	ll n;
	while (cin >> n) {
		ll sum[5001];
		ll ans = -9000000000;
		roop(i, n) {
			cin >> sum[i];
			if (i != 0) { sum[i] += sum[i - 1]; }
			ans = max(ans, sum[i]);
		}
		for (ll i = 0; i < n - 1; i++) {

			ll	sumi = sum[i];

			for (ll j = i + 1; j < n; j++) {

				ll sumj = sum[j];
				ans = max(ans, sumj - sumi);
			}
		}
		cout << ans << endl;
	}
	return 0;
}

C++: #include <cstdio>
#include <algorithm>
#define INF 1e+18
#define MAX_SIZE 1 << 17
using namespace std;

typedef long long ll;

int n,k;
ll v[100000];
ll segMax[2][2 * MAX_SIZE - 1],segAdd[2][2 * MAX_SIZE - 1];

void add(int num,int a,int b,ll x,int k = 0,int l = 0,int r = n){
	if(b <= l || r <= a) return;
	if(a <= l && r <= b){
		segAdd[num][k] += x;
		return;
	}
	add(num,a,b,x,k * 2 + 1,l,(l + r) / 2);
	add(num,a,b,x,k * 2 + 2,(l + r) / 2,r);
	segMax[num][k] = max(segMax[num][k * 2 + 1] + segAdd[num][k * 2 + 1],segMax[num][k * 2 + 2] + segAdd[num][k * 2 + 2]);
}

ll get(int num,int a,int b,int k = 0,int l = 0,int r = n){
	if(b <= l || r <= a) return -INF;
	if(a <= l && r <= b) return segAdd[num][k] + segMax[num][k];
	return max(get(num,a,b,k * 2 + 1,l,(l + r) / 2),get(num,a,b,k * 2 + 2,(l + r) / 2,r)) + segAdd[num][k];
}

void init(){
	int t = 1;
	while(t < n + 1) t *= 2;
	for(int i = 0;i < t * 2 - 1;i++){
		segMax[0][i] = -INF;
		segMax[1][i] = -INF;
	}
	segMax[0][t - 1] = 0;
	for(int i = 0;i < n;i++) segMax[0][i + t] = segMax[0][i + t - 1] + v[i];
	ll ma = -INF;
	for(int i = n;i >= 0;i--) {
		ma = max(ma,segMax[0][i + t - 1]);
		segMax[1][i + t - 1] = ma - segMax[0][i + t - 1];
	}
	for(int i = t - 2;i >= 0;i--) {
		segMax[0][i] = max(segMax[0][i * 2 + 1],segMax[0][i * 2 + 2]);
		segMax[1][i] = max(segMax[1][i * 2 + 1],segMax[1][i * 2 + 2]);
	}
	n = t;
}

int main(){
	/*scanf("%d %d",&n,&k);
	for(int i = 0;i < n;i++) scanf("%lld",&v[i]);
	init();
	for(int i = 0;i < k - 1;i++){
		
	}
	printf("%lld\n",get(1,0,n));*/
	while(1){
		ll ma = -INF;
		scanf("%d",&n);
		if(!n) break;
		for(int i = 0;i < n;i++){
			scanf("%lld",&v[i]);
			ma = max(ma,v[i]);
		}
		init();
		if(ma < 0) printf("%lld\n",ma);
		else printf("%lld\n",get(1,0,n));
	}
	return 0;
}

C++: #include <iostream>
#include <vector>
#include <algorithm>
#include <set>
#include <queue>
#include <stack>
#include <string>
#include <map>
#include <cstdio>
#include <cstdlib>
#include <cmath>

#define rep(i, n) for(int i = 0; i < n; i ++)
#define ALL(T) T.begin(), T.end()

using namespace std;

typedef pair<int, int> pii;
typedef unsigned long long ull;

const int L = -(int)1e6;

int main(void){
    for(int n, res, sum; cin >> n, n; cout << res << endl){
        sum = 0; res = L;
        while(n --){
            int a; cin >> a;

            sum += a;
            if(sum < 0){
                sum = 0;
                if(res < a) res = a;
            }
            else if(res < sum) res = sum;
        }
    }

    return 0;
}

C++: #define _USE_MATH_DEFINES
#include<iostream>
#include<vector>
#include<algorithm>
#include<string>
#include<cmath>
#include<list>
#include<stack>
#include<queue>
#include<cctype>
#include<iomanip>
#include<functional>
#include<numeric>
#define EPS 1e-10
#define INF (-(1<<21))
using namespace std;
typedef long long llong;
int main() {
	int n;
	while (1) {
		cin >> n;
		if (!n)break;
		vector<vector<int>>v(n, vector<int>(n));
		vector<int>a(n);
		for (int i = 0; i < n; i++)cin >> a[i];
		for (int i = 0; i < n; i++) {
			for (int j = 0; j < n; j++) {
				if (i == j)v[i][j] = a[i];
				else v[i][j] = INF;
			}
		}
		int max = INF;
		for (int i = 0; i < n; i++) {
			for (int j = i; j < n; j++) {
				if (i == j) {
					//cout << v[i][j] << " ";
					continue;
				}
				v[i][j] = v[i][j - 1] + a[j];
				if (max < v[i][j])max = v[i][j];
				//cout << v[i][j] << " ";
			}
			//cout << endl;
		}
		cout << max << endl;
	}
	return 0;
}

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

int main() {
	int i, j, n, a, max_so_far, max_ending_here;
	
	while (1) {
		cin >> n;
		if (n == 0)break;
		max_so_far = 0;
		max_ending_here = 0;
		for (i = 0; i < n; i++) {
			cin >> a;
			max_ending_here = max_ending_here + a;
			if (max_ending_here < 0)max_ending_here = 0;
			if (max_so_far < max_ending_here)max_so_far = max_ending_here;
			if (max_so_far < a)max_so_far = a;
		}
		cout << max_so_far << endl;

	}

	return 0;
}

C++: #include <bits/stdc++.h>
using namespace std;
int main(){
    while(1){
        int n;
        cin>>n;
        if(n==0){
            return 0;
        }
        vector<int> a(n);
        for(int i=0;i<n;i++){
            cin>>a.at(i);
        }
        vector<int> b(n+1);
        b.at(0)=0;
        for(int i=1;i<=n;i++){
            b.at(i)=b.at(i-1)+a.at(i-1);
        }
        int ans;
        for(int i=1;i<=n;i++){
            for(int j=0;j<i;j++){
                ans=max(ans,b.at(i)-b.at(j));
            }
        }
        cout<<ans<<endl;
    }
}

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;
    }
}