| #include <bits/stdc++.h> |
|
|
| using namespace std; |
|
|
| typedef pair <int,int> pii; |
|
|
| int tc, l, r, M, pib, _max; |
| vector <pii> v,ans; |
|
|
| int main(){ |
| scanf("%d", &tc); |
| while(tc--){ |
| v.clear(), ans.clear(); |
| scanf("%d", &M); |
| while(scanf("%d %d", &l, &r), l + r) v.push_back( make_pair(l, r) ); |
| sort(v.begin(), v.end()); |
| l = _max = 0; |
| for(int i = 0; i < v.size(); i++){ |
| pib = -1; |
| for(int j = i; j < v.size(); j++){ |
| if(v[j].first > l){ |
| i = j - 1; |
| break; |
| } |
| if(v[j].second > _max) _max = v[j].second, pib = j; |
| } |
| if(pib == -1) break; |
| ans.push_back(v[pib]), l = _max; |
| if(_max >= M) break; |
| } |
| if(ans.back().second < M) ans.clear(); |
| printf("%d\n", (int)ans.size()); |
| for(int i = 0; i < ans.size(); i++) printf("%d %d\n", ans[i].first, ans[i].second); |
| if(tc) putchar('\n'); |
| } |
| return(0); |
| } |
|
|
