Buggy python submission (verdict: Time Limit Exceeded):
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[[1]*(m+1)for _ in range(n+1)]
dp[0][0]=1
for i in range(1,n+1):
    for j in range(1,m+1):
        dp[i][j]=dp[i-1][j]+dp[i][j-1]
        if s[i-1]!=t[j-1]:
            dp[i][j]-=dp[i-1][j-1]
        dp[i][j]%=10**9+7
print(dp[n][m])

Fixed submission:
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[(m+1)*[1]for _ in range(n+1)]
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]
    else:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]-dp[i][j]
    dp[i+1][j+1]%=mod
print(dp[-1][-1])

Buggy python submission (verdict: Time Limit Exceeded):
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp1=[1]*(m+1)
dp2=[1]*(m+1)
for i in range(n):
  if i%2==0:
    for j in range(m):
      if s[i]==t[j]:dp1[j+1]=dp2[j+1]+dp1[j]
      else:dp1[j+1]=dp2[j+1]+dp1[j]-dp2[j]
      dp1[j+1]%=mod
  else:
    for j in range(m):
      if s[i]==t[j]:dp2[j+1]=dp1[j+1]+dp2[j]
      else:dp2[j+1]=dp1[j+1]+dp2[j]-dp1[j]
      dp2[j+1]%=mod
if n%2==0:print(dp2[-1])
else:print(dp1[-1])

Fixed submission:
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[(m+1)*[1]for _ in range(n+1)]
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]
    else:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]-dp[i][j]
    dp[i+1][j+1]%=mod
print(dp[-1][-1])

Buggy python submission (verdict: Time Limit Exceeded):
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp1=[1]*(m+1)
dp2=[1]*(m+1)
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp1[j+1]=dp2[j+1]+dp1[j]
    else:dp1[j+1]=dp2[j+1]+dp1[j]-dp2[j]
    dp1[j+1]%=mod
  dp2=dp1.copy()
  dp1=[1]*(m+1)
print(dp2[-1])

Fixed submission:
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[(m+1)*[1]for _ in range(n+1)]
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]
    else:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]-dp[i][j]
    dp[i+1][j+1]%=mod
print(dp[-1][-1])

Buggy python submission (verdict: Runtime Error):
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp1=[1]*(m+1)
dp2=[1]*(m+1)
for i in range(n):
  for j in range(m):
    if s[i]==t[i]:dp1[j+1]=dp2[j+1]+dp1[j]
    else:dp1[j+1]=dp2[j+1]+dp1[j]-dp2[j]
    dp1[j+1]%=mod
  dp2=dp1
  dp1=[1]*(m+1)
print(dp2[-1])

Fixed submission:
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[(m+1)*[1]for _ in range(n+1)]
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]
    else:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]-dp[i][j]
    dp[i+1][j+1]%=mod
print(dp[-1][-1])

Buggy python submission (verdict: Time Limit Exceeded):
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[(m+1)*[1]for _ in range(n+1)]
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]
    else:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]-dp[i][j]
    dp[i+1][j+1]%=mod
print(dp[-1][-1])

Fixed submission:
mod=10**9+7
n,m=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
dp=[(m+1)*[1]for _ in range(n+1)]
for i in range(n):
  for j in range(m):
    if s[i]==t[j]:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]
    else:dp[i+1][j+1]=dp[i][j+1]+dp[i+1][j]-dp[i][j]
    dp[i+1][j+1]%=mod
print(dp[-1][-1])