Järjestys

n = int(input())
t = [int(i) for i in input().split(" ")]
pairs = zip(t, list(range(1, n+1)))
order = list(zip(*sorted(pairs)))[1]


BIT = [0]*(n+1)
def add(pos,val):
	while pos <=n+1:
		BIT[pos]+=val
		pos+=(pos&-pos)

def get(pos):
	ans=0
	while pos > 0:
		ans+=BIT[pos]
		pos-=(pos&-pos)
	return ans;

adjust = [0]*n
for i in range(n):
	adjust[i]=i-get(t[i])
	add(t[i],1)


res = ""
m = 0
for x in reversed(order):
	a = x-adjust[x-1]
	if (a > 1):
		res += str(a-1) +" "+ str(a) +" "
		m += 2
	if (n > 1):	
		res += str(n) +" "+ str(n-1) +" "
		m += 2
	n -= 1
print(m)
print(res[:-1])

Test 1

Group: 1

Verdict: ACCEPTED

Test 2

Group: 2

Verdict: ACCEPTED

Test 3

Group: 3

Verdict: ACCEPTED