MathematicsForCP.java

package math;
	import java.util.Arrays;

	public class MathematicsForCP {

		public static void main(String[] args) {
			
//			boolean isPrime[] = seiveOfEratoSthenes(20);
//			for(int i = 0; i<=20; i++) {
//				System.out.println(i +" " + isPrime[i]);
//			}
			
//			System.out.println(gcd(24, 60));
			
			System.out.println(fastPower(3978432, 5, 1000000007));
			
		}	
		
		static long fastPower(long a, long b, int n) {
			
			long res = 1;
			
			while ( b > 0) {
				
				if ( (b&1) != 0) {
					res = (res * a % n) % n;
				}
				
				a = (a % n * a % n) % n;
				b =  b >> 1;
			}
			
			return res;
			
		}
		
		
		static int gcd(int a, int b) {
			
			return a % b == 0 ? b : gcd ( b, a%b);
		}
		
		
		
		
		static boolean[] seiveOfEratoSthenes(int n) {
			
			boolean isPrime[] = new boolean[n+1];
			
			Arrays.fill(isPrime, true);
			
			isPrime[0] = false;
			isPrime[1] = false;
			
			for(int i = 2; i * i <= n; i++) {
				
				
				for(int j = 2*i; j<=n; j += i) {
					isPrime[j] = false;
				}
				
			}
			
			return isPrime;
			
		}

	}