题目链接：
http://acm.hust.edu.cn/vjudge/contest/121332#problem/F
Description
You have a positive integer m and a non-negative integer s. Your task is to find the smallest and the largest of the numbers that have length m and sum of digits s. The required numbers should be non-negative integers written in the decimal base without leading zeroes.
Input
The single line of the input contains a pair of integers m, s (1 ≤ m ≤ 100, 0 ≤ s ≤ 900) — the length and the sum of the digits of the required numbers.
Output
In the output print the pair of the required non-negative integer numbers — first the minimum possible number, then — the maximum possible number. If no numbers satisfying conditions required exist, print the pair of numbers "-1 -1" (without the quotes).
Sample Input
Input
2 15
Output
69 96
Input
3 0
Output
-1 -1
题意：
给出m和s，分别找出最大和最小的非负整数，满足数位长度为m，数位和为s;
题解：
直接贪心枚举每一位就可以了；
最小：能放0就放0; (首位不能是0)
最大：能放9就放9;
WA一次：题目特地强调了非负整数；
那么考虑s为0的情况，并不是全为-1 -1;
当m=1 s=0时应输出0 0;
代码：
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