【微软2014实习生】 String reorder

问题描述：

Time Limit: 10000ms
Case Time Limit: 1000ms
Memory Limit: 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.

Sample In
aabbccdd
007799aabbccddeeff113355zz
1234.89898
abcdefabcdefabcdefaaaaaaaaaaaaaabbbbbbbddddddee

Sample Out
abcdabcd
013579abcdefz013579abcdefz
<invalid input string>
abcdefabcdefabcdefabdeabdeabdabdabdabdabaaaaaaa

基本思路：利用map容器实现，统计每个字符的个数，然后逐个输出，直到该字符的个数为0。

#include<iostream>#include<string>#include<map>using namespace std;string errormsg ="<invalid input string>";string getresult(string str){map<char,int> mp;string reslut ="";if(str.empty())return errormsg;if(str.size()==0)return errormsg;for(string::size_type i=0;i<str.size();i++){char temp= str[i];if((temp<='z'&& temp>='a')||(temp<='9'&& temp>='0')){mp[temp]++;}else{return errormsg;}}bool isover = false;while(!isover){isover = true;map<char,int>::iterator iter = mp.begin();for(;iter!=mp.end();iter++){if(iter->second>0){isover = false;reslut +=iter->first;iter->second--;}}}return reslut;}int main(void) {string str;while(getline(cin,str)){string res= getresult(str);cout<<res<<endl;;cin.ignore();}return 0;}