习题8-15(uva-1617)

#include <iostream>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>


#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;
const int maxn = 1e5 + 7;
struct Node {
    
    
	int l, r;
	bool operator<(const Node& input) {
    
    
		return r < input.r || (r == input.r && l < input.l);
	}
}nodes[maxn];
int n;
int main()
{
    
    
	int t;
	cin >> t;
	while (t--)
	{
    
    
		cin >> n;
		for (int i = 0; i < n; i++) {
    
    
			cin >> nodes[i].l >> nodes[i].r;
		}
		sort(nodes, nodes + n);
		int ans = 0,cur = nodes[0].r;

		for (int i = 0; i < n; i++) {
    
    
			if(nodes[i].r == cur) continue;
			if (nodes[i].l <= cur && nodes[i].r > cur) {
    
    
				cur++;
			}
			else if(nodes[i].l > cur) {
    
    
				ans++;
				cur = nodes[i].r;
			}
		}
		cout << ans << endl;
	}
}