Buggy python submission (verdict: Runtime Error):
N = int(input())
X = list(map(int,input().split()))
import numpy as np
import math
ans = 0
mod = 10**9+7
x=X[-1]
for i in range(N-1):
  for j in range(i+1,N-1):
    a = j-i-1
    ans += ((X[j]-X[i])%mod)*(math.factorial(a)%mod)*(math.factorial(N-1)%mod*pow(math.factorial(a+2),mod-2,mod))%mod
    
for k,y in enumerate(X[:N-1:]):
  a = N-k-2
  ans+=((x-y)%mod)*(math.factorial(a)%mod)*(math.factorial(N-1)%mod*pow(math.factorial(a+1),mod-2,mod))%mod
print(ans%mod)


Fixed submission:
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += pow(i+1,mod-2,mod)
  ans += ((X[i+1]-X[i])%mod)*(a%mod)
  ans %= mod
  
ans *= math.factorial(N-1)%mod

print(ans%mod)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
X = list(map(int,input().split()))
ans = 0
mod = 10**9+7
l=[1]*(N+1)
a=1
for i in range(2,N+1):
  a*=i
  a%=mod
  l[i]=a
x=X[-1]
for i in range(N-1):
  for j in range(i+1,N-1):
    a = j-i-1
    ans += (X[j]-X[i])*(l[a])%mod*l[N-1]%mod*pow(l[a+2],mod-2,mod)%mod
    
for k,y in enumerate(X[:N-1:]):
  a = N-k-2
  ans+=(x-y)*l[a]%mod*l[N-1]%mod*pow(l[a+1],mod-2,mod)%mod
print(ans%mod)

Fixed submission:
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += pow(i+1,mod-2,mod)
  ans += ((X[i+1]-X[i])%mod)*(a%mod)
  ans %= mod
  
ans *= math.factorial(N-1)%mod

print(ans%mod)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
X = list(map(int,input().split()))
ans = 0
mod = 10**9+7
l=[1]*(N+1)
a=1
for i in range(2,N+1):
  a*=i
  a%=mod
  l[i]=a
x=X[-1]
for i in range(N-1):
  for j in range(i+1,N-1):
    a = j-i-1
    ans += (X[j]-X[i])*(l[a])%mod*l[N-1]%mod*pow(l[a+2],mod-2,mod)%mod
    
for k,y in enumerate(X[:N-1:]):
  a = N-k-2
  ans+=(x-y)*l[a]%mod*l[N-1]%mod*pow(l[a+1],mod-2,mod)%mod
print(ans%mod)


Fixed submission:
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += pow(i+1,mod-2,mod)
  ans += ((X[i+1]-X[i])%mod)*(a%mod)
  ans %= mod
  
ans *= math.factorial(N-1)%mod

print(ans%mod)

Buggy python submission (verdict: Runtime Error):
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += (1/(i+1))*math.factorial(N-1)
  ans += (X[i+1]-X[i]%mod)*(a%mod)

print(int(ans)%mod)

Fixed submission:
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += pow(i+1,mod-2,mod)
  ans += ((X[i+1]-X[i])%mod)*(a%mod)
  ans %= mod
  
ans *= math.factorial(N-1)%mod

print(ans%mod)

Buggy python submission (verdict: Runtime Error):
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += 1/(i+1)
  ans += (X[i+1]-X[i])*a

ans *= math.factorial(N-1)
print(int(ans)%mod)

Fixed submission:
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += pow(i+1,mod-2,mod)
  ans += ((X[i+1]-X[i])%mod)*(a%mod)
  ans %= mod
  
ans *= math.factorial(N-1)%mod

print(ans%mod)

Buggy python submission (verdict: Time Limit Exceeded):
N = int(input())
X = list(map(int,input().split()))
import numpy as np
import math
ans = 0
mod = 10**9+7
x=X[-1]
for i in range(N-1):
  for j in range(i+1,N-1):
    a = j-i-1
    ans += ((X[j]-X[i])%mod)*(math.factorial(a)%mod)*(math.factorial(N-1)%mod*pow(math.factorial(a+2),mod-2,mod))%mod
    
for k,y in enumerate(X[:N-1:]):
  a = N-k-2
  ans+=((x-y)%mod)*(math.factorial(a)%mod)*(math.factorial(N-1)%mod*pow(math.factorial(a+1),mod-2,mod))%mod
print(ans%mod)

Fixed submission:
N = int(input())
X = list(map(int,input().split()))
import math
ans = 0
mod = 10**9+7
a = 0
ans = 0
for i in range(N-1):
  a += pow(i+1,mod-2,mod)
  ans += ((X[i+1]-X[i])%mod)*(a%mod)
  ans %= mod
  
ans *= math.factorial(N-1)%mod

print(ans%mod)