ACM——2的n次方

import java.util.Scanner;
public class Main {

    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        char str[]=new char[1000];
        str[999]=‘1‘;
        for(int i=0;i<999;i++){
            str[i]=‘0‘;
        }
        int power;
        Scanner cin=new Scanner(System.in);
        power=cin.nextInt();
        int plus=0;
        for(int i=0;i<power;i++){
                for(int j=999;j>=0;j--){
                    int temp=(str[j]-‘0‘)*2%10+plus;
                    plus=(str[j]-‘0‘)*2/10;
                    str[j]=(char) (temp+‘0‘);
                }
        }
        
        int pos = 0;
        while(str[pos]==‘0‘){
            pos++;
        }
        for(;pos<1000;pos++){
            System.out.print(str[pos]);
        }
        System.out.println();
    }

}