Buggy python submission (verdict: Runtime Error):
from functools import lru_cache

ri = lambda S: [int(v) for v in S.split()]


def rii():
    return ri(input())


N, M, K = rii()
A = rii()
B = rii()

i = j = 0


@lru_cache(None)
def dp(i, j, k):
    ki = kj = mki = mkj = 0

    if i < N:
        Ki = k - A[i] if A[i] <= k else 0
        mki = 1 + dp(i + 1, j, Ki) if Ki >= 0 else 0
    if j < M:
        kj = k - B[j] if B[j] <= k else 0
        mkj = 1 + dp(i, j + 1, kj) if kj >= 0 else 0

    return max(mki, mkj)


print(dp(0, 0, K))
#print(dp.cache_info())


Fixed submission:
from itertools import accumulate
from bisect import bisect_left

ri = lambda S: [int(v) for v in S.split()]


def rii():
    return ri(input())


N, M, K = rii()
A = rii()
B = rii()

i = j = 0

pA = [0] + list(accumulate(A))
pB = [0] + list(accumulate(B))

ans = 0
for i, a in enumerate(pA):
    br = 0
    if K >= a:
        r = K - a
        br = i
    
    if r:
        j = bisect_left(pB, r)
        if j != len(pB):
            if pB[j] > r:
                j -= 1
            br += j
    
    ans = max(ans, br)

print(ans)

Buggy python submission (verdict: Runtime Error):
ri = lambda S: [int(v) for v in S.split()]


def rii():
    return ri(input())


N, M, K = rii()
A = rii()
B = rii()

i = j = 0


def dp(i, j, k):
    ki = kj = mki = mkj = 0

    if i < N:
        Ki = k - A[i] if A[i] <= k else 0
        mki = 1 + dp(i + 1, j, Ki) if Ki >= 0 else 0
    if j < M:
        kj = k - B[j] if B[j] <= k else 0
        mkj = 1 + dp(i, j + 1, kj) if kj >= 0 else 0

    return max(mki, mkj)


print(dp(0, 0, K))


Fixed submission:
from itertools import accumulate
from bisect import bisect_left

ri = lambda S: [int(v) for v in S.split()]


def rii():
    return ri(input())


N, M, K = rii()
A = rii()
B = rii()

i = j = 0

pA = [0] + list(accumulate(A))
pB = [0] + list(accumulate(B))

ans = 0
for i, a in enumerate(pA):
    br = 0
    if K >= a:
        r = K - a
        br = i
    
    if r:
        j = bisect_left(pB, r)
        if j != len(pB):
            if pB[j] > r:
                j -= 1
            br += j
    
    ans = max(ans, br)

print(ans)

Buggy python submission (verdict: Runtime Error):
ri = lambda S: [int(v) for v in S.split()]


def rii():
    return ri(input())


N, M, K = rii()
A = rii()
B = rii()

i = j = 0


def dp(i, j, k):
    print(i, j, k)
    ki = kj = mki = mkj = 0

    if i < N:
        Ki = k - A[i] if A[i] <= k else 0
        mki = 1 + dp(i + 1, j, Ki) if Ki >= 0 else 0
    if j < M:
        kj = k - B[j] if B[j] <= k else 0
        mkj = 1 + dp(i, j + 1, kj) if kj >= 0 else 0

    return max(mki, mkj)


print(dp(0, 0, K))


Fixed submission:
from itertools import accumulate
from bisect import bisect_left

ri = lambda S: [int(v) for v in S.split()]


def rii():
    return ri(input())


N, M, K = rii()
A = rii()
B = rii()

i = j = 0

pA = [0] + list(accumulate(A))
pB = [0] + list(accumulate(B))

ans = 0
for i, a in enumerate(pA):
    br = 0
    if K >= a:
        r = K - a
        br = i
    
    if r:
        j = bisect_left(pB, r)
        if j != len(pB):
            if pB[j] > r:
                j -= 1
            br += j
    
    ans = max(ans, br)

print(ans)