Buggy python submission (verdict: Runtime Error):
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log2(A_i + 1)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += 1
                        num[j] -= 1
                        break
                    elif num[j] >= 2:
                        add = num[j] // 2
                        ans += add
                        num[j] = num[j] % 2
                        break
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)


Fixed submission:
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log(A_i + 1, 2)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += min(num[j], num[i])
                        num[j] = max(num[j] - num[i], 0)
                        break
                    elif num[j] >= 2:
                        add = num[j] // 2
                        ans += add
                        num[j] = num[j] % 2
                        break
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)

Buggy python submission (verdict: Runtime Error):
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log2(A_i + 1)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += 1
                        num[j] -= 1
                        break
                    elif num[j] >= 2:
                        ans += 1
                        num[j] -= 2
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)


Fixed submission:
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log(A_i + 1, 2)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += min(num[j], num[i])
                        num[j] = max(num[j] - num[i], 0)
                        break
                    elif num[j] >= 2:
                        add = num[j] // 2
                        ans += add
                        num[j] = num[j] % 2
                        break
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import bisect
import math

N = int(input())
A = list(map(int, input().split()))
A.sort()

ans = 0
used = [0] * N
for i in range(N - 1, 0, -1):
    if used[i] == 0:
        A_i = A[i]
        comp = 2 ** math.ceil(math.log(A_i + 1, 2)) - A_i
        j = bisect.bisect_left(A, comp, 0, i - 1)
        while True:
            if A[j] == comp:
                if used[j] == 0:
                    ans += 1
                    used[j] = 1
                    break
                else:
                    if j + 1 < i:
                        j += 1
                    else:
                        break
            else:
                break

print(ans)


Fixed submission:
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log(A_i + 1, 2)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += min(num[j], num[i])
                        num[j] = max(num[j] - num[i], 0)
                        break
                    elif num[j] >= 2:
                        add = num[j] // 2
                        ans += add
                        num[j] = num[j] % 2
                        break
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)

Buggy python submission (verdict: Time Limit Exceeded):
import bisect
import math

N = int(input())
A = list(map(int, input().split()))
A.sort()

ans = 0
used = [0] * N
for i in range(N - 1, 0, -1):
    if used[i] == 0:
        A_i = A[i]
        comp = 2 ** math.ceil(math.log2(A_i + 1)) - A_i
        j = bisect.bisect_left(A, comp, 0, i - 1)
        while True:
            if A[j] == comp:
                if used[j] == 0:
                    ans += 1
                    used[j] = 1
                    break
                else:
                    if j + 1 < i:
                        j += 1
                    else:
                        break
            else:
                break

print(ans)


Fixed submission:
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log(A_i + 1, 2)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += min(num[j], num[i])
                        num[j] = max(num[j] - num[i], 0)
                        break
                    elif num[j] >= 2:
                        add = num[j] // 2
                        ans += add
                        num[j] = num[j] % 2
                        break
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)

Buggy python submission (verdict: Runtime Error):
import bisect
import math

N = int(input())
A = list(map(int, input().split()))
A.sort()

ans = 0
used = [0] * N
for i in range(N-1, -1, -1):
    if used[i] == 0:
        A_i = A[i]
        comp = 2 ** math.ceil(math.log2(A_i+1)) - A_i
        j = bisect.bisect_left(A, comp, 0, i-1)
        if A[j] == comp and used[j] == 0:
            ans += 1
            used[j] = 1

print(ans)


Fixed submission:
import bisect
import math
import sys
input = sys.stdin.readline


N = int(input())
A = list(map(int, input().split()))
A.sort()
A_set = []
num = []
a_cur = float('inf')
for a in A:
    if a != a_cur:
        A_set.append(a)
        num.append(1)
        a_cur = a
    else:
        num[-1] += 1

ans = 0
for i in range(len(A_set) - 1, -1, -1):
    if num[i] > 0:
        A_i = A_set[i]
        comp = 2 ** math.ceil(math.log(A_i + 1, 2)) - A_i
        j = bisect.bisect_left(A_set, comp, 0, i)
        while True:
            if A_set[j] == comp:
                if num[j] > 0:
                    if i != j:
                        ans += min(num[j], num[i])
                        num[j] = max(num[j] - num[i], 0)
                        break
                    elif num[j] >= 2:
                        add = num[j] // 2
                        ans += add
                        num[j] = num[j] % 2
                        break
                    else:
                        break
                else:
                    break
            else:
                break

print(ans)