高效率的幂运算
例子：2^64==?
package heng.java.level2;import java.util.Scanner;public class powTest {public static void main(String[] args) {Scanner input = new Scanner(System.in);while(input.hasNext()){int x = input.nextInt();int n = input.nextInt();long value = pow(x,n);System.out.println(value);}}public static boolean isEven(int m){boolean flag = false;if(m % 2 == 0){flag = true;}return flag;}public static long pow(long x, int n){if(n == 0){return 1;}if(n == 1){return x;}if(isEven(n)){//判断是不是偶数return pow(x*x, n/2);}else{return pow(x*x,n/2)*x;}}}