Jubilee

#include <bits/stdc++.h>
using namespace std;
 
typedef long long ll;
#define For(type, i, a, b) for (type i = (a); i <= (b); ++i)

ll n, m, k, u, v, x;
ll res;
const ll mod = 1e9 + 7;

void FastIn(){
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
}
 
void ReadIn(){
  cin >> n >> m;
  k = ((m - 2) % mod * (m - 2) % mod) % mod;
//   res = ((m % mod * (m - 1) % mod) % mod * pow((m - 1) % mod, n - 1) % mod) % mod + ((m % mod * (m - 1) % mod) % mod * pow(((m - 2) % mod * (m - 2) % mod) % mod, n - 1) % mod) % mod;
//   res = res % mod;

  u = m - 1;
  v = k;
  For(ll, i, 1, n - 1){
    u = (u % mod * (m - 1) % mod) % mod;
  }

  For(ll, i, 1, n - 2){
    v = ((v % mod * (m % mod * k % mod)) % mod) % mod;
  }
  x = m % mod * (m - 1) % mod;
  res = (m % mod * u % mod) % mod + (x % mod * v % mod) % mod;
  res = (res % mod + mod) % mod; 
  cout << res;
}
int main(){
    FastIn();
    ReadIn();
}
// g++ -o output
// g++ F.cpp
// ./f.out

// 1000000 1000000000

Test 1

Verdict: ACCEPTED

Test 2

Verdict: ACCEPTED

Test 3

Verdict: WRONG ANSWER

Test 4

Verdict: ACCEPTED

Test 5

Verdict: WRONG ANSWER

Test 6

Verdict: WRONG ANSWER

Test 7

Verdict: ACCEPTED

Test 8

Verdict: ACCEPTED

Test 9

Verdict: ACCEPTED

Test 10

Verdict: ACCEPTED

Test 11

Verdict: WRONG ANSWER

Test 12

Verdict: WRONG ANSWER

Test 13

Verdict: WRONG ANSWER

Test 14

Verdict: WRONG ANSWER