Pair sort

import sys 
input_d = sys.stdin.read().split()
n = int(input_d[0])
arr = [int(i) for i in input_d[1:]]
swaps = []
idx = 0

#have dic with position for each key before iterating so i avoid for i in range(n) everytime using the number as key :D
swapcount = 0

pos = {}
for i in range(len(arr)) :
    if not arr[i] in pos.keys():
        pos[arr[i]] = [i]
    else :
        pos[arr[i]].append(i)
#print(pos)





idx = 0
for i in range(n-1):
    elem = arr[idx]
    a = pos.get(elem)[0]
    b = pos.get(elem)[1]

    toswap = b if a == idx else a 
    ind =  1 if a == idx else 0
    elemswapped = arr[idx+1]
    indswapped = 0 if idx+1 == pos.get(elemswapped)[0] else 1

    #print(toswap)
    if idx < len(arr) -1 :
        swaps.append([toswap+1,idx+1+1])
        pos.get(elem)[ind] = idx+1
        pos.get(elemswapped)[indswapped]= toswap
        #print("elem we swap for",pos.get(elem))
        #print("elem we sawpped out",pos.get(elemswapped))
        arr[toswap], arr[idx+1] = arr[idx+1], arr[toswap] #swap them
        idx+=2
        swapcount+=1



#print(arr)
print(swapcount)
for s in swaps:
    print(*s)



'''for i in range(n-1):
    elem = arr[idx]
    print("elem is",elem)
    print("idx is ",idx)
    if idx + 1 < len(arr): 
        if arr[idx]==arr[idx+1]:
            idx+=2
        else :
            toswap = arr[idx+1:].index(elem)
            swaps.append([idx+1,toswap])
            #swapping
            temp = arr[idx+1]
            arr[idx+1] = arr[toswap]
            arr[toswap] = temp
            swapcount +=1
            idx+=2'''
'''
print(swapcount)

print(arr)
print(swaps)'''
#print(arr)

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: ACCEPTED

Test 4

Verdict: ACCEPTED

Test 5

Verdict: ACCEPTED

Test 6

Verdict: ACCEPTED

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: ACCEPTED

Test 12

Verdict: ACCEPTED

Test 13

Verdict: ACCEPTED

Test 14

Verdict: ACCEPTED