UVA_10020_Minimal coverage

#include<iostream>
#include<sstream>
#include<string>
#include<vector>
#include<list>
#include<set>
#include<map>
#include<stack>
#include<queue>
#include<algorithm>
#pragma warning(disable:4996)
#include<cstdio>
#include<cstdlib>
using std::cin;
using std::cout;
using std::endl;
using std::stringstream;
using std::string;
using std::vector;
using std::list;
using std::pair;
using std::set;
using std::multiset;
using std::map;
using std::multimap;
using std::stack;
using std::queue;
using std::priority_queue;
int main()
{
	//freopen("input.txt", "r", stdin);  
	//freopen("output.txt", "w", stdout);  
	int T;
	while (cin >> T)
	{
		sign:
		while (T--)
		{
			int n; cin >> n;
			vector<pair<int, int>>segment;
			vector<int>result;
			int left, right;
			while (cin >> left >> right)
			{
				if (!left&&!right)
				{
					break;
				}
				if (right<0 || left>n)
				{
					continue;
				}
				segment.push_back({ left,right });
			}
			right = 0;
			int j = 1000000000;
			for (int i = 0; i != segment.size(); i++)
			{
				if (segment[i].first <= 0 && segment[i].second > right)
				{
					j = i;
					right = segment[i].second;
				}
			}
			if (j == 1000000000)
			{
				cout << '0' << endl;
				if (T)
				{
					cout << endl;
				}
				continue;
			}
			else
			{
				result.push_back(j);
			}
			size_t i = 0;
			do
			{
				left = right;
				if (right >= n)
				{
					break;
				}
				int k = 1000000000;
				for (j=0;j!=segment.size();j++)
				{
					if (segment[j].first <= left&&segment[j].second > right)
					{
						right = segment[j].second;
						k = j;
					}
				}
				if (k == 1000000000)
				{
					cout << '0' << endl;
					if (T)
					{
						cout << endl;
					}
					goto sign;
				}
				else
				{
					result.push_back(k);
				}
				i++;
			}while(i!=segment.size());
			cout << result.size() << endl;
			for (size_t i = 0; i < result.size(); i++)
			{
				cout << segment[result[i]].first << ' ' << segment[result[i]].second << endl;
			}
			if (T)
			{
				cout << endl;
			}
		}
	}
	return 0;
}