C++ Quick-Find Algorithm

QuickFind.cpp

#include <stdio.h>
#define N 10000
main()
{
    int i, p, q, t, id[ N ];

    for ( i = 0; i < N; i++ ) id[ i ] = i;

    while ( scanf( "%d %d\n", &p, &q ) == 2 )
    { 
        if ( id[ p ] == id[ q ] ) continue;

        for ( t = id[ p ], i = 0; i < N; i++ )

          if ( id[ i ] == t ) id[ i ] = id[ q ];
        printf( " %d %d\n", p, q );
    }
}