zoj 2510 Concentric Rings

#include <iostream>#include <cstdlib>#include <cstdio>#include <algorithm>using namespace std;struct node{      int in;      int out;}a[10000];int cmp(const void* a,const void* b){      return ((*(node*)a).out - (*(node*)b).out);  }int main(){    int n,i,tmp,cot;    while(scanf("%d",&n)!=EOF)    {          cot = 1;          for(i = 0;i < n;i ++)          scanf("%d%d",&a[i].in,&a[i].out);          qsort(a,n,sizeof(a[0]),cmp);          tmp = a[0].out;          for(i = 1;i < n;i ++)          {     if(a[i].in >= tmp)     {cot ++;tmp = a[i].out;     }          }          printf("%dn",n - cot);    }    return 0;}