Problem:
Maximum Sum Sequence

Given a sequence of numbers a1, a2, a3, ..., an, find the maximum sum of a contiguous subsequence of those numbers. Note that, a subsequence of one element is also a contiquous subsequence.

Input

The input consists of multiple datasets. Each data set consists of:

n
a1
a2
.
.
an

You can assume that 1 ≤ n ≤ 5000 and -100000 ≤ ai ≤ 100000.

The input end with a line consisting of a single 0.

Output

For each dataset, print the maximum sum in a line.

Sample Input

7
-5
-1
6
4
9
-6
-7
13
1
2
3
2
-2
-1
1
2
3
2
1
-2
1
3
1000
-200
201
0

Output for the Sample Input

19
14
1001

Solution in C++ (judge verdict: Wrong Answer)

#include <iostream>
#include <vector>
#include <algorithm>

using namespace std;

int debug = 0;

int main(void){
	int n, m, i, j, k;
	int tmp, max;
	bool first = 0;
	vector<int> intv;

	while(cin >> n){
		if(n == 0){
			break;
		}else{
			//ÇÝÝ
			for(i=0;i<n;i++){
				cin >> m;
				intv.push_back(m);
				//if(debug) cout << "int[" << i << "] =" << intv[i] << endl; 
			}

			//vfð¸ç·
			tmp=0;
			for(i=1;i<intv.size();i++){
				if(intv[tmp] > 0){
					if(intv[i] > 0){ //¯Èç
						intv[tmp] += intv[i];
						intv[i] = 0;
					}else{ //ÙÈç
						tmp = i;
					}
				}else if(intv[tmp] < 0){
					if(intv[i] < 0){
						intv[tmp] += intv[i];
						intv[i] = 0;
					}else{
						tmp = i;
					}
				}
			}
			/*
			if(debug){
				for(i=0;i<intv.size();i++){
					cout << intv[i] <<endl;
				}
				cout << "----------------------" << endl;
			}
			*/
			intv.erase( remove(intv.begin(), intv.end(), 0), intv.end());
			/*
			if(debug){
				for(i=0;i<intv.size();i++){
					cout << intv[i] <<endl;
				}
			}
			*/

			int vsize = intv.size();
			for(i=1;i<=vsize;i+=2){//i:Â
				//if(debug) cout << "number =" << i << endl;
				for(j=0;j<=vsize-1-i+1;j++){ //j:JnÊu
					tmp = 0;
					for(k=0;k<i;k++){
						tmp += intv[j+k];
					}
					//if(debug) cout << "tmp ==" << tmp << endl;
					if(first == false){
						max = tmp;
						first = true;
					}else if(max < tmp){
						max = tmp;
					}
				}
			}
			cout << max << endl;
			intv.clear();
			first = false;
		}
	}
	return 0;
}