Problem p02782 (python)

Fixed submission:
mod = 10 ** 9 + 7
N = 2 * 10 ** 6 + 10

fac = [0] * N
finv = [0] * N
inv = [0] * N

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, N):
    fac[i] = fac[i - 1] * i % mod
    # mod pにおける1, 2, ..., nの逆元
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod


def com(n, k):
    global fac, finv, mod
    if n < k:
        return 0
    if n < 0 or k < 0:
        return 0
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod

def g(r, c):
    return (com(r + c + 2, r + 1) - 1) % mod

r1, c1, r2, c2 = map(int, input().split())

answer = g(r2, c2) - g(r2, c1 - 1) - g(r1 - 1, c2) + g(r1 - 1, c1 - 1)
answer %= mod
print(answer)

Buggy submission (verdict: Runtime Error):
mod = 10 ** 9 + 7
N = 2 * 10 ** 6

fac = [0] * N
finv = [0] * N
inv = [0] * N

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, N):
    fac[i] = fac[i - 1] * i % mod
    # mod pにおける1, 2, ..., nの逆元
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod


def com(n, k):
    global fac, finv, mod
    if n < k:
        return 0
    if n < 0 or k < 0:
        return 0
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod


r1, c1, r2, c2 = map(int, input().split())
answer = 0

for r in range(r1, r2 + 1):
    for c in range(c1, c2 + 1):
        answer += com(r + c, c)
        answer %= mod
print(answer)

Buggy submission (verdict: Runtime Error):
mod = 10 ** 9 + 7
N = 10 ** 6

fac = [0] * N
finv = [0] * N
inv = [0] * N

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, N):
    fac[i] = fac[i - 1] * i % mod
    # mod pにおける1, 2, ..., nの逆元
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod


def com(n, k):
    global fac, finv, mod
    if n < k:
        return 0
    if n < 0 or k < 0:
        return 0
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod


r1, c1, r2, c2 = map(int, input().split())
answer = 0

for r in range(r1, r2 + 1):
    for c in range(c1, c2 + 1):
        answer += com(r + c, c)
        answer %= mod
print(answer)

Buggy submission (verdict: Runtime Error):
mod = 10 ** 9 + 7
N = 10 ** 6

fac = [0] * N
finv = [0] * N
inv = [0] * N

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, N):
    fac[i] = fac[i - 1] * i % mod
    # mod pにおける1, 2, ..., nの逆元
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod


def com(n, k):
    global fac, finv, mod
    if n < k:
        return 0
    if n < 0 or k < 0:
        return 0
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod


r1, c1, r2, c2 = map(int, input().split())
answer = 0

for r in range(r1, r2 + 1):
    for c in range(c1, c2 + 1):
        answer += com(r + c, c)
print(answer % mod)

Buggy submission (verdict: Runtime Error):
from operator import mul
from functools import reduce


mod = 10 ** 9 + 7
N = 10 ** 6

fac = [0] * N
finv = [0] * N
inv = [0] * N

fac[0] = fac[1] = 1
finv[0] = finv[1] = 1
inv[1] = 1
for i in range(2, N):
    fac[i] = fac[i - 1] * i % mod
    # mod pにおける1, 2, ..., nの逆元
    inv[i] = mod - inv[mod % i] * (mod // i) % mod
    finv[i] = finv[i - 1] * inv[i] % mod


def com(n, k):
    global fac, finv, mod
    if n < k:
        return 0
    if n < 0 or k < 0:
        return 0
    return fac[n] * (finv[k] * finv[n - k] % mod) % mod


r1, c1, r2, c2 = map(int, input().split())
answer = 0

for r in range(r1, r2 + 1):
    for c in range(c1, c2 + 1):
        answer += com(r + c, c)
print(answer % mod)