题解

#include<bits/stdc++.h>
using namespace std;
struct program{
	int s;
    int e;
}a[100001];
int n;
bool cmp(program aa,program bb){
	return aa.e < bb.e;
}
int main(){
    int t;
    cin>>t;
    while(t--){
		cin>>n;
        for(int i=1;i<=n;i++) cin>>a[i].s>>a[i].e;
        sort(a+1,a+n+1,cmp);
        int cnt =1;
        int ans =a[1].e;
        for(int i=2;i<=n;i++){
			if(ans<a[i].s){
				cnt++;
                ans=a[i].e;
            } 
        } 
        cout<<cnt<<endl;
    }
   
    return 0;
}