rq242 大地的秘密

rq242 大地的秘密

#include < iostream >
using   namespace  std;

int  n;
int  a[ 100010 ];
int  b[ 100010 ];
int  c[ 100010 ];
int  size;
int  cal( int  ai){
     int  l = 1 ,r = size;
     while (l <= r){
         int  mid = (l + r) >> 1 ;
         if (ai > c[mid - 1 ] && ai <= c[mid])  return  mid;
         else   if (ai < c[mid]) r = mid - 1 ;
         else  l = mid + 1 ;
    }
}
int  main()
{
    scanf( " %d " , & n);
     int  x;
     for ( int  i = 1 ;i <= n; ++ i){
        scanf( " %d " , & x);
        a[x] = i;
    }
     for ( int  i = 1 ;i <= n; ++ i){
        scanf( " %d " , & x);
        b[a[x]] = i;
    }
    c[ 1 ] = b[ 1 ]; size = 1 ;
     for ( int  i = 2 ;i <= n; ++ i){
         int  j;
         if (b[i] < c[ 1 ]) j = 1 ;
         else   if (b[i] > c[size]) j =++ size;
         else  j = cal(b[i]);
        c[j] = b[i];
    }
    printf( " %d\n " ,n - size);
     return   0 ;
}