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()))
mod=10**9+7
sm=[[ 0 for i in range(M)] for j in range(N)]
s1=0
s2=0
if N>M:
  for i in range(N):
    if t[0]==s[i]:
      a=1
    else:
      a=0
    s1=s1+a
    sm[i][0]=s1
    if i<M:
      if s[0]==t[i]:
        a=1
      else:
        a=0
      s2=s2+a
      sm[0][i]=s2
else:
  for i in range(M):
    if s[0]==t[i]:
      a=1
    else:
      a=0
    s2=s2+a
    sm[0][i]=s2
    if i<N:
      if t[0]==s[i]:
        a=1
      else:
        a=0
      s1=s1+a
      sm[i][0]=s1
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      sm[i][j]=sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]
    else:
      sm[i][j]=sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+sm[i-1][j-1]+1
ans=(sm[N-1][M-1]+1)%mod
print(ans)

Fixed submission:
N,M=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
mod=10**9+7
sm=[[ 0 for i in range(M)] for j in range(N)]
s1=0
s2=0
if N>M:
  for i in range(N):
    if t[0]==s[i]:
      a=1
    else:
      a=0
    s1=s1+a
    sm[i][0]=s1
    if i<M:
      if s[0]==t[i]:
        a=1
      else:
        a=0
      s2=s2+a
      sm[0][i]=s2
else:
  for i in range(M):
    if s[0]==t[i]:
      a=1
    else:
      a=0
    s2=s2+a
    sm[0][i]=s2
    if i<N:
      if t[0]==s[i]:
        a=1
      else:
        a=0
      s1=s1+a
      sm[i][0]=s1
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1])%mod
    else:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+sm[i-1][j-1]+1)%mod
ans=(sm[N-1][M-1]+1)%mod
print(ans)

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()))
mod=10**9+7
dp=[[ 0 for i in range(M)] for j in range(N)]
sm=[[ 0 for i in range(M)] for j in range(N)]
s1=0
s2=0
if N>M:
  for i in range(N):
    if t[0]==s[i]:
      dp[i][0]=1
    s1=s1+dp[i][0]
    sm[i][0]=s1
    if i<M:
      if s[0]==t[i]:
        dp[0][i]=1
      s2=s2+dp[0][i]
      sm[0][i]=s2
else:
  for i in range(M):
    if s[0]==t[i]:
      dp[0][i]=1
    s2=s2+dp[0][i]
    sm[0][i]=s2
    if i<N:
      if t[0]==s[i]:
        dp[i][0]=1
      s1=s1+dp[i][0]
      sm[i][0]=s1

for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      dp[i][j]=0
    else:
      dp[i][j]=sm[i-1][j-1]+1
    sm[i][j]=sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+dp[i][j]
ans=(sm[N-1][M-1]+1)%mod
print(ans)

Fixed submission:
N,M=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
mod=10**9+7
sm=[[ 0 for i in range(M)] for j in range(N)]
s1=0
s2=0
if N>M:
  for i in range(N):
    if t[0]==s[i]:
      a=1
    else:
      a=0
    s1=s1+a
    sm[i][0]=s1
    if i<M:
      if s[0]==t[i]:
        a=1
      else:
        a=0
      s2=s2+a
      sm[0][i]=s2
else:
  for i in range(M):
    if s[0]==t[i]:
      a=1
    else:
      a=0
    s2=s2+a
    sm[0][i]=s2
    if i<N:
      if t[0]==s[i]:
        a=1
      else:
        a=0
      s1=s1+a
      sm[i][0]=s1
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1])%mod
    else:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+sm[i-1][j-1]+1)%mod
ans=(sm[N-1][M-1]+1)%mod
print(ans)

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()))
mod=10**9+7
c=[0]*N
d=[0]*M
dp=[[ 0 for i in range(M)] for j in range(N)]
sm=[[ 0 for i in range(M)] for j in range(N)]
for i in range(N):
  if t[0]==s[i]:
    dp[i][0]=1
    c[i]=1
for i in range(M):
  if s[0]==t[i]:
    dp[0][i]=1
    d[i]=1
s1=0
for i in range(N):
  s1=s1+c[i]
  sm[i][0]=s1
s1=0
for i in range(M):
  s1=s1+d[i]
  sm[0][i]=s1
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      dp[i][j]=0
    else:
      dp[i][j]=sm[i-1][j-1]+1
    sm[i][j]=sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+dp[i][j]
ans=(sm[N-1][M-1]+1)%mod
print(ans)

Fixed submission:
N,M=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
mod=10**9+7
sm=[[ 0 for i in range(M)] for j in range(N)]
s1=0
s2=0
if N>M:
  for i in range(N):
    if t[0]==s[i]:
      a=1
    else:
      a=0
    s1=s1+a
    sm[i][0]=s1
    if i<M:
      if s[0]==t[i]:
        a=1
      else:
        a=0
      s2=s2+a
      sm[0][i]=s2
else:
  for i in range(M):
    if s[0]==t[i]:
      a=1
    else:
      a=0
    s2=s2+a
    sm[0][i]=s2
    if i<N:
      if t[0]==s[i]:
        a=1
      else:
        a=0
      s1=s1+a
      sm[i][0]=s1
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1])%mod
    else:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+sm[i-1][j-1]+1)%mod
ans=(sm[N-1][M-1]+1)%mod
print(ans)

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()))
mod=10**9+7
c=[0]*N
d=[0]*M
dp=[[ 0 for i in range(M)] for j in range(N)]
sm=[[ 0 for i in range(M)] for j in range(N)]
for i in range(N):
  if t[0]==s[i]:
    dp[i][0]=1
    c[i]=1
for i in range(M):
  if s[0]==t[i]:
    dp[0][i]=1
    d[i]=1
for i in range(N):
  sm[i][0]=sum(c[0:i+1])
for i in range(M):
  sm[0][i]=sum(d[0:i+1])
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      dp[i][j]=0
    else:
      dp[i][j]=sm[i-1][j-1]+1
    sm[i][j]=sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+dp[i][j]
ans=(sm[N-1][M-1]+1)%mod
print(ans)

Fixed submission:
N,M=map(int,input().split())
s=list(map(int,input().split()))
t=list(map(int,input().split()))
mod=10**9+7
sm=[[ 0 for i in range(M)] for j in range(N)]
s1=0
s2=0
if N>M:
  for i in range(N):
    if t[0]==s[i]:
      a=1
    else:
      a=0
    s1=s1+a
    sm[i][0]=s1
    if i<M:
      if s[0]==t[i]:
        a=1
      else:
        a=0
      s2=s2+a
      sm[0][i]=s2
else:
  for i in range(M):
    if s[0]==t[i]:
      a=1
    else:
      a=0
    s2=s2+a
    sm[0][i]=s2
    if i<N:
      if t[0]==s[i]:
        a=1
      else:
        a=0
      s1=s1+a
      sm[i][0]=s1
for i in range(1,N):
  for j in range(1,M):
    if s[i] != t[j]:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1])%mod
    else:
      sm[i][j]=(sm[i-1][j]+sm[i][j-1]-sm[i-1][j-1]+sm[i-1][j-1]+1)%mod
ans=(sm[N-1][M-1]+1)%mod
print(ans)