数字构造问题

★问题描述

给定一个只包含数字[0..9]的字符串，请使用字符串中的某些字符，构建一个能够整除

15最大的整数。注意，字符串中的每个字符只能使用一次。

★编程任务

求由给定字符串构造的能够整除15的最大整数。

★数据输入

由文件input.txt给出输入数据。输入数据为一个只包含数字[0..9]字符串，字符串的长度

为1..1000。如果无法构建出该数字，请输出“impossible”。

★数据输出

将程序运行结果输出到文件output.txt中。输出一行数字串。-★ issue of the number of structures to describe the problem to only include the number of a [0 .. 9] of the string, use some of the character string to build a 15, the largest integer divisible. Note that each string of characters can only be used once. ★ programming tasks for a given string from the structure to the greatest integer divisible by 15. ★ data input is given by the input data file input.txt. Input data include only the number of a [0 .. 9] string, the string length of 1 .. 1000. If you can not build out the figures, please output " impossible" . ★ run data output will be output to a file in output.txt. Output line number of string.