Buggy python submission (verdict: Time Limit Exceeded):
def f(x):
    k = int(x)
    return c[k], k


c = [0, 2, 5, 5, 4, 5, 6, 3, 7, 6]
N, M = list(map(int, input().split()))
A = list(map(f, input().split()))
A = sorted(A, key=lambda x: x[0] * 10 - x[1])

# 数字を作成するのに必要なマッチ数のリストを作成
b = []
dic = {}
n = 0
for d in A:
    if n != d[0]:
        b.append(d[0])
        n = d[0]
        dic[n] = d[1]

ans = [0] * b[0]
n = b[0]
while True:
    max_ = 0
    for d in b:
        if n - d == 0:
            if dic[d] > max_:
                max_ = dic[d]
        elif n - d > 0 and ans[n - d] > 0:
            t = dic[d] * (10 ** len(str(ans[n - d]))) + ans[n - d]
            max_ = max(max_, t)

    if n == N:
        print(max_)
        break
    ans.append(max_)
    n += 1

Fixed submission:
def f(x):
    k = int(x)
    return c[k], k


c = [0, 2, 5, 5, 4, 5, 6, 3, 7, 6]
N, M = list(map(int, input().split()))
A = list(map(f, input().split()))
A = sorted(A, key=lambda x: x[0] * 10 - x[1])

# 数字を作成するのに必要なマッチ数のリストを作成
b = []
dic = {}
n = 0
for d in A:
    if n != d[0]:
        b.append(d[0])
        n = d[0]
        dic[n] = d[1]

ans = [0] * b[0]
n = b[0]
while True:
    max_ = 0
    for d in b:
        if n - d == 0:
            if dic[d] > max_:
                max_ = dic[d]
        elif n - d > 0 and ans[n - d] > 0:
            t = ans[n - d] * 10 + dic[d]
            max_ = max(max_, t)

    if n == N:
        print(max_)
        break
    ans.append(max_)
    n += 1

Buggy python submission (verdict: Runtime Error):
c = [0,2,5,5,4,5,6,3,7,6]
N, M = list(map(int, input().split()))
A = list(map(int, input().split()))

B = [0] * M
for i in range(M):
    B[i] = c[A[i]]

x = min(B)
value = 0
for i in range(M):
    if B[i] == x:
        value = max(A[i], value)
y = N % x
if y == 0:
    print(str(value) * (N / x))
else:
    k = 10
    for i in range(M):
        if B[i] % x == y:
            if k > B[i]:
                k = B[i]
                l = A[i]
            elif k == B[i]:
                l = max(l, A[i])
    if value > l:
        print(str(value) * ((N - k) // x) + str(l))
    else:
        print(str(l) + str(value) * ((N - k) // x))

Fixed submission:
def f(x):
    k = int(x)
    return c[k], k


c = [0, 2, 5, 5, 4, 5, 6, 3, 7, 6]
N, M = list(map(int, input().split()))
A = list(map(f, input().split()))
A = sorted(A, key=lambda x: x[0] * 10 - x[1])

# 数字を作成するのに必要なマッチ数のリストを作成
b = []
dic = {}
n = 0
for d in A:
    if n != d[0]:
        b.append(d[0])
        n = d[0]
        dic[n] = d[1]

ans = [0] * b[0]
n = b[0]
while True:
    max_ = 0
    for d in b:
        if n - d == 0:
            if dic[d] > max_:
                max_ = dic[d]
        elif n - d > 0 and ans[n - d] > 0:
            t = ans[n - d] * 10 + dic[d]
            max_ = max(max_, t)

    if n == N:
        print(max_)
        break
    ans.append(max_)
    n += 1

Buggy python submission (verdict: Runtime Error):
c = [0,2,5,5,4,5,6,3,7,6]
N, M = list(map(int, input().split()))
A = list(map(int, input().split()))

B = [0] * M
for i in range(M):
    B[i] = c[A[i]]

x = min(B)
value = 0
for i in range(M):
    if B[i] == x:
        value = max(A[i], value)
y = N % x
if y == 0:
    print(str(value) * (N / x))
else:
    k = 10
    for i in range(M):
        if B[i] % x == y:
            if k > B[i]:
                k = B[i]
                l = A[i]
            elif k == B[i]:
                l = max(l, A[i])
    if value > l:
        print(str(value) * ((N - k) // x) + str(l))
    else:
        print(str(l) + str(value) * ((N - k) / x))

Fixed submission:
def f(x):
    k = int(x)
    return c[k], k


c = [0, 2, 5, 5, 4, 5, 6, 3, 7, 6]
N, M = list(map(int, input().split()))
A = list(map(f, input().split()))
A = sorted(A, key=lambda x: x[0] * 10 - x[1])

# 数字を作成するのに必要なマッチ数のリストを作成
b = []
dic = {}
n = 0
for d in A:
    if n != d[0]:
        b.append(d[0])
        n = d[0]
        dic[n] = d[1]

ans = [0] * b[0]
n = b[0]
while True:
    max_ = 0
    for d in b:
        if n - d == 0:
            if dic[d] > max_:
                max_ = dic[d]
        elif n - d > 0 and ans[n - d] > 0:
            t = ans[n - d] * 10 + dic[d]
            max_ = max(max_, t)

    if n == N:
        print(max_)
        break
    ans.append(max_)
    n += 1