C :

#include<stdio.h>
#include<stdlib.h>
struct Arr
{
	int l,w;
}arr[50001];

int cmp(const void * a,const void * b)
{
	struct Arr *c=(struct Arr *)a;
	struct Arr *d=(struct Arr *)b;
	if(c->l!=d->l)
		return c->l - d->l;
	else
		return c->w - d->w;
}

int main()
{
	int T,N,i,j,t;
	scanf("%d",&T);
	while(T--)
	{
		int count=0;
		scanf("%d",&N);
		for(i=0;i<N;i++)
			scanf("%d%d",&arr[i].l,&arr[i].w);
		qsort(arr,N,sizeof(arr[0]),cmp);
		for(i=0;i<N;i++)
		{
			if(arr[i].w!=0)
			{
				t=arr[i].w;
			    count++;
		    	for(j=i+1;j<N;j++)
				{
			    	if(t<=arr[j].w)
					{
						t=arr[j].w;
						arr[j].w=0;
					}
				}
			}
		}
		printf("%d\n",count);
	}
	return 0;
}

C++ :

#include<stdio.h>
#include<string.h>
#include<algorithm>
using namespace std;
struct mb
{
    int len;
    int weight;
}w[10001];
bool cmp(mb x,mb y) //排序
{
    if(x.len<y.len)  return true;  //升序
    if(x.len==y.len&&x.weight<y.weight)  return true;
    return false;
}
int main()
{
    int s,n,i,j,count,t;
    scanf("%d",&s);
    while(s--)
    {
        count=0;
        scanf("%d",&n);
        for(i=0;i<=n-1;i++)
        {
            scanf("%d %d",&w[i].len,&w[i].weight);
        }
        sort(w,w+n,cmp);
        for(i=0;i<=n-1;i++)
        {
            if(w[i].weight!=0) //数未出现过
            {
                t=w[i].weight;
                count++;  //开启一单位
                for(j=i+1;j<=n-1;j++)
                {
                    if(w[j].weight>=t)
                    {
                        t=w[j].weight;
                        w[j].weight=0;
                    }
                }
             }
         }
         printf("%d\n",count);
    }
    return 0;
}