Buggy python submission (verdict: Runtime Error):
N, M, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A_sum = [0]
for i in range(N):
    A_sum.append(A_sum[i] + A[i])
B_sum = [0]
for i in range(N):
    B_sum.append(B_sum[i] + B[i])
B_sum.append(10**10)

res = 0
for i in range(len(A_sum)):
    low = 0
    high = len(B_sum)
    while high - low > 1:
        mid = (low + high) // 2
        if A_sum[i] + B_sum[mid] <= K:
            low = mid
        else:
            high = mid
    if A_sum[i] + B_sum[low] <= K:
        res = max(res, i + low)

print(res)


Fixed submission:
N, M, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A_sum = [0]
for i in range(N):
    A_sum.append(A_sum[i] + A[i])
B_sum = [0]
for i in range(M):
    B_sum.append(B_sum[i] + B[i])
B_sum.append(10**10)

res = 0
for i in range(len(A_sum)):
    low = 0
    high = len(B_sum)
    while high - low > 1:
        mid = (low + high) // 2
        if A_sum[i] + B_sum[mid] <= K:
            low = mid
        else:
            high = mid
    if A_sum[i] + B_sum[low] <= K:
        res = max(res, i + low)

print(res)

Buggy python submission (verdict: Time Limit Exceeded):
N, M, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A_sum = [0] + [sum(A[:i+1]) for i in range(len(A))]
B_sum = [0] + [sum(B[:i+1]) for i in range(len(B))]
B_sum.append(10**20)

res = 0
for i in range(len(A_sum)):
    low = 0
    high = len(B_sum)
    while high - low > 1:
        mid = (low + high) // 2
        if A_sum[i] + B_sum[mid] <= K:
            low = mid
        else:
            high = mid
    if A_sum[i] + B_sum[low] <= K:
        res = max(res, i + low)

print(res)


Fixed submission:
N, M, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A_sum = [0]
for i in range(N):
    A_sum.append(A_sum[i] + A[i])
B_sum = [0]
for i in range(M):
    B_sum.append(B_sum[i] + B[i])
B_sum.append(10**10)

res = 0
for i in range(len(A_sum)):
    low = 0
    high = len(B_sum)
    while high - low > 1:
        mid = (low + high) // 2
        if A_sum[i] + B_sum[mid] <= K:
            low = mid
        else:
            high = mid
    if A_sum[i] + B_sum[low] <= K:
        res = max(res, i + low)

print(res)

Buggy python submission (verdict: Time Limit Exceeded):
N, M, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A_sum = [0] + [sum(A[:i+1]) for i in range(len(A))]
B_sum = [0] + [sum(B[:i+1]) for i in range(len(B))]

res = 0
for i in range(len(A_sum)):
    low = 0
    high = len(B_sum)
    while high - low > 1:
        mid = (low + high) // 2
        if A_sum[i] + B_sum[mid] <= K:
            low = mid
        else:
            high = mid
    if A_sum[i] + B_sum[low] <= K:
        res = max(res, i + low)

print(res)


Fixed submission:
N, M, K = map(int, input().split())
A = list(map(int, input().split()))
B = list(map(int, input().split()))

A_sum = [0]
for i in range(N):
    A_sum.append(A_sum[i] + A[i])
B_sum = [0]
for i in range(M):
    B_sum.append(B_sum[i] + B[i])
B_sum.append(10**10)

res = 0
for i in range(len(A_sum)):
    low = 0
    high = len(B_sum)
    while high - low > 1:
        mid = (low + high) // 2
        if A_sum[i] + B_sum[mid] <= K:
            low = mid
        else:
            high = mid
    if A_sum[i] + B_sum[low] <= K:
        res = max(res, i + low)

print(res)