唉！差一点就超时了。
891ms
#include <stdio.h>
#include <stdlib.h>
int main( void )
{
    int i, j, key, sets, *a, num, step, temp;
    scanf("%d", &sets ) ;
    while( sets-- ){
        scanf("%d", &num ) ;
        a = ( int*)malloc( num*sizeof(int) ) ;
        for( i = 0; i < num; ++i )
        	scanf("%d", &a[i] ) ;
        step = 0 ;
        for( i = 0; i < num; ++i ){
        	key = i ;
        	for( j = i+1; j < num; ++j )
                if( a[key] > a[j] )
                	key = j ;
            if( key != i ){
            	temp = a[key] ;
            	a[key] = a[i] ;
            	a[i] = temp ;
            	++ step ;
            }
        }
        free( a ) ;
        printf("%d\n", step ) ;
    }
    return 0 ;
}