Buggy python submission (verdict: Runtime Error):
from math import pow

  
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q)%mod+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q)%mod + c*3) % mod
    q += 1
print(int(abc))

Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))

Buggy python submission (verdict: Runtime Error):
from math import pow

  
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q)+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q) + c*3) % mod
    q += 1
print(int(abc))

Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))

Buggy python submission (verdict: Runtime Error):
def mul(a, b):
    return ((a % mod) * (b % mod)) % mod

def power(x, y):
    if   y == 0     : return 1
    elif y == 1     : return x % mod
    elif y % 2 == 0 : return power(x, y/2)**2 % mod
    else            : return power(x, y/2)**2 * x % mod

  
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (power(3,q)+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (power(3,q) + c*3) % mod
    q += 1
print(abc)


Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (3**q+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (3**q + c*3) % mod
    q += 1
print(abc)


Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (3**q+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (3**q + c*3) % mod
    q += 1
print(abc)


Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (3**q+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (3**q + c*3) % mod
    q += 1
print(abc)


Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))

Buggy python submission (verdict: Time Limit Exceeded):
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in reversed(s):
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (3**q+c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (3**q + c*3) % mod
    q += 1
print(abc)


Fixed submission:
s = input()
mod = 10**9 + 7
abc = 0
bc = 0
c = 0
q = 0
for i in s[::-1]:
  if i == "A":
    abc = (abc + bc) % mod
  if i == "B":
    bc = (bc + c) % mod
  if i == "C":
    c = (pow(3,q,mod) + c) % mod
  if i == "?":
    abc = (abc*3 + bc) % mod
    bc = (bc*3 + c) % mod 
    c = (pow(3,q,mod) + c*3) % mod
    q += 1
print(int(abc))