微软2014实习生及秋令营技术类职位在线测试（题目1 : String reorder）

题目1 : String reorder

时间限制:10000ms

单点时限:1000ms

内存限制:256MB

Description

For this question, your program is required to process an input string containing only ASCII characters between ‘0’ and ‘9’, or between ‘a’ and ‘z’ (including ‘0’, ‘9’, ‘a’, ‘z’).

Your program should reorder and split all input string characters into multiple segments, and output all segments as one concatenated string. The following requirements should also be met,
1. Characters in each segment should be in strictly increasing order. For ordering, ‘9’ is larger than ‘0’, ‘a’ is larger than ‘9’, and ‘z’ is larger than ‘a’ (basically following ASCII character order).
2. Characters in the second segment must be the same as or a subset of the first segment; and every following segment must be the same as or a subset of its previous segment.

Your program should output string “<invalid input string>” when the input contains any invalid characters (i.e., outside the '0'-'9' and 'a'-'z' range).

Input

Input consists of multiple cases, one case per line. Each case is one string consisting of ASCII characters.

Output

For each case, print exactly one line with the reordered string based on the criteria above.

样例输入

aabbccdd
007799aabbccddeeff113355zz
1234.89898
abcdefabcdefabcdefaaaaaaaaaaaaaabbbbbbbddddddee

样例输出

abcdabcd
013579abcdefz013579abcdefz
<invalid input string>
abcdefabcdefabcdefabdeabdeabdabdabdabdabaaaaaaa

用map比较好，这个程序耗时太多，哎。。。

代码如下：

#include <iostream>
//#include <map>
#include <vector>
#include <list>
#include <algorithm>
#include <string>
using namespace std;

bool checkstr(string a)
{
	for (unsigned int i=0;i<a.size();i++)
	{
		if (a[i]<'0'||a[i]>'z'||('9'<a[i]&&a[i]<'a'))
		{
			return false;
		}
	}
	return true;
}

int main()
{
	string sa;
	vector<string> va;
	list<char>::iterator it1;
	//while(cin>>sa)
	while(getline(cin,sa))
	{
		va.push_back(sa);
	}
	vector<list<char> > la(va.size());
	
	for (unsigned int i=0;i<va.size();i++)
	{
		for (unsigned int j=0;j<va[i].size();j++)
		{
			la[i].push_back(va[i][j]);
		}
		la[i].sort();
	}

	for (unsigned int i=0;i<va.size();i++)
	{
		if (checkstr(va[i]))
		{
			char temp;
			it1=la[i].begin();
			while (!la[i].empty())
			{
				cout<<*it1;
				temp=*it1;
				it1=la[i].erase(it1);
				if (it1==la[i].end()&&!la[i].empty())
				{
					it1=la[i].begin();

				}
				while(!la[i].empty()&&*it1==temp)
				{
					++it1;
					if (it1==la[i].end()&&!la[i].empty())
					{
						it1=la[i].begin();
					}
				}
			}
			cout<<endl;
		}
		else
			cout<<"<invalid input string>"<<endl;
	}

	//system("pause");
	return 0;
}