sz = 2000;
x = [];
for(i = 0; i < sz; i++)
	append(x, i);
y = copy(x);
for(i = sz/2; i > 0; i--){
	listdel(x, i*2-1);
}
printf("length: %d\n", length(x));
//foreach(lambda(v){printf("%d\n", v);}, x);
for(i = 0; i < sz/2; i++)
	listins(x, i*2+1, i*2+1);
//foreach(lambda(v){printf("%d\n", v);}, x);
printf("length: %d\n", length(x));
printf("x == y -> %d\n", equal(x, y));