C. Given Length and Sum of Digits...
time limit per test
1 secondmemory limit per test
256 megabytesinput
standard inputoutput
standard outputYou 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 test(s)
Input
2 15
Output
69 96
Input
3 0
Output
-1 -1
题意:要求出两个m位数,他们m位上数字的和为s,求出最小和最大的这种数,假设不存在,就输出-1 -1
贪心的策略,希望数字最小,那么除了第m位,其它位尽可能为9。希望数字最大,那么尽量让前几位为9
#include<cstdio> #include<cstring> #include <iostream> #include<algorithm> using namespace std; int m,s; int main() { while(~scanf("%d%d",&m,&s)) { if((s<1&&m>1)||s>m*9) { cout<<-1<<" "<<-1<<endl; continue; } for(int i=m-1,k=s;i>=0;i--) { int j=max(0,k-9*i); if(j==0&&i==m-1&&k) j=1;//k!=0非常关键。当数据为1 0时,若k=0则此时要输出0 cout<<j; k-=j; } cout<<" "; for(int i=m-1,k=s;i>=0;i--) { int j=min(9,k); cout<<j; k-=j; } } return 0; }