Codeforces Olesya and Rodion

题目解析：大数问题，使用Java的BigInteger

import java.math.BigInteger;import java.util.Scanner;public class OlesyaAndRodion {public static void main(String[] args) {Scanner scanner = new Scanner(System.in);//字符串转化为大数BigInteger k = new BigInteger(1+"");//设置为0BigInteger r = new BigInteger(0+"");//取第一个数BigInteger p = new BigInteger(10+"");int n = scanner.nextInt();int t = scanner.nextInt();if(n == 1 && t== 10) {System.out.println(-1);} else {n--;//求p的幂，p初始是10p = p.pow(n);for(int i = 1;; i++) {//求余，并和0比较if(p.mod(BigInteger.valueOf(t)).compareTo(r) == 0) {System.out.println(p);break;}//p+1p = p.add(k);}}}}