Ways to paint N paintings such that adjacent paintings don’t have same colors in C programming

In this problem, you are given N painting and we have m color that we can make paintings with and we need to find the number of ways in which we can draw the painting such that none of the same color paintings are to each other.

The program’s output can have very large values and handing these values is a bit problem so we will calculate its answer in standard modulo 10⁹ +7.

The formula to find the number ways is :

Ways = n*(m-1)(n-1)

Example to describe the problem, this will need the number of paintings n and number of colors m :

Input

n = 5 ,m = 6

Output

3750

Example

#include <iostream>
#include<math.h>
#define modd 1000000007
using namespace std;
unsigned long find(unsigned long x,
unsigned long y, unsigned long p) {
   unsigned long res = 1;
   x = x % p;
   while (y > 0) {
      if (y & 1)
         res = (res * x) % p;
      y = y >> 1;
      x = (x * x) % p;
   }
   return res;
}
int ways(int n, int m) {
   return find(m - 1, n - 1, modd) * m % modd;
}
int main() {
   int n = 5, m = 6;
   cout<<"There are"<<ways(n, m)<<"ways";
   return 0;
}

Output

There are 3750 ways