Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
AN = list((map(int,input().split(" "))))
 
AN.sort(reverse=True)
 
num = 0
count = 0
 
def bbb(ccc):
    ddd = ccc
    while True:
        if ddd == 2:
            return True
        ddd = ddd / 2
        if ddd % 2 != 0:
            return False
 
while True:
 
    if len(AN) == 0:
        break
 
    A = AN.pop(num)
 
    for i in range(len(AN)):
        n = A + AN[i]
        if (n & (n - 1) == 0):
            AN.pop(i)
            count += 1
            break
 
print(count)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0

for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1

print(ans)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Buggy python submission (verdict: Runtime Error):
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0

for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        count += 1
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1

print(ans)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
AN = list((map(int,input().split(" "))))

AN.sort(reverse=True)

num = 0
count = 0
ccc = 0

while True:

    if len(AN) == 0:
        break

    A = AN.pop(num)
    ccc += 1

    for i in range(len(AN)):
        n = A + AN[i]
        if (n & (n - 1) == 0):
            AN.pop(i)
            count += 1
            break
    
    if ccc > 200001:
        break

print(count)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
AN = list((map(int,input().split(" "))))

AN.sort(reverse=True)

num = 0
count = 0

def bbb(ccc):
    ddd = ccc
    while True:
        if ddd == 2:
            return True
        ddd = ddd / 2
        if ddd % 2 != 0:
            return False

while True:

    if len(AN) == 0:
        break

    A = AN.pop(num)

    for i in range(len(AN)):
        n = A + AN[i]
        if (n & (n - 1) == 0):
            AN.pop(i)
            count += 1
            break

print(count)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
AN = list((map(int,input().split(" "))))

AN.sort(reverse=True)

num = 0
count = 0

def bbb(ccc):
    ddd = ccc
    while True:
        if ddd == 2:
            return True
        ddd = ddd / 2
        if ddd % 2 != 0:
            return False

while True:

    if len(AN) == 0:
        break

    A = AN.pop(num)

    for i in range(len(AN)):
        if bbb(A + AN[i]):
            AN.pop(i)
            count += 1
            break

print(count)

Fixed submission:
N = int(input())
A = list(map(int,input().split(" ")))
A.sort()
used = [0] * N
pow2_set = reversed([ 1<<i for i in range(36)])
ans = 0
for pow2 in pow2_set:
    l,r = 0,N-1
    while l < r:
        if A[l] + A[r] < pow2:
            l += 1
        elif A[l] + A[r] == pow2:
            if used[l] == 0 and used[r] == 0:
                ans += 1
                used[l],used[r] = 1,1
            else:
                if used[l] == 1:
                    l += 1
                if used[r] == 1:
                    r -= 1
        else:
            r -= 1
 
print(ans)