ural 1078. Segments

ural 1078. Segments

#include < iostream >
using   namespace  std;

struct  arr{
     int  x,y,c;
}a[ 501 ];
int  N;
int  f[ 501 ];
int  p[ 501 ];
int  cmp( const   void *  no1, const   void *  no2){
    arr  * nox = (arr * )no1, * noy = (arr * )no2;
     if (nox -> x != noy -> x)  return  nox -> x - noy -> x;
}
int  main()
{
    scanf( " %d " , & N);
     for ( int  i = 0 ;i < N; ++ i){
        scanf( " %d%d " , & a[i].x, & a[i].y);
        a[i].c = i + 1 ;
    }
    qsort(a,N, sizeof (arr),cmp);
     int  Max = 0 ,pre;
     for ( int  i = 0 ;i < N; ++ i){
        f[i] = 1 ; p[i] = i;
         for ( int  j = 0 ;j < i; ++ j)
             if (a[i].x > a[j].x && a[j].y > a[i].y)
                 if (f[i] < f[j] + 1 ){
                    f[i] = f[j] + 1 ;
                    p[i] = j;
                }
         if (f[i] > Max){
            Max = f[i];
            pre = i;
        }
         else   if (f[i] == Max)
             if (a[p[i]].c < a[pre].c)
                pre = i;
    }
    printf( " %d\n " ,Max);
     while (pre != p[pre]){
        printf( " %d  " ,a[pre].c);
        pre = p[pre];
    }
    printf( " %d\n " ,a[pre].c);
     return   0 ;
}