POJ 3096 surprising_string (coding with STL )

[Description]:

The D-pairs of a string of letters are the ordered pairs of letters that are distance D from each other. A string is D-unique if all of its D-pairs are different. A string is surprising if it is D-unique for every possible distance D.

Consider the string ZGBG. Its 0-pairs are ZG, GB, and BG. Since these three pairs are all different, ZGBG is 0-unique. Similarly, the 1-pairs of ZGBG are ZB and GG, and since these two pairs are different, ZGBG is 1-unique. Finally, the only 2-pair of ZGBG is ZG, so ZGBG is 2-unique. Thus ZGBG is surprising. (Note that the fact that ZG is both a 0-pair and a 2-pair of ZGBG is irrelevant, because 0 and 2 are different distances.)

Acknowledgement: This problem is inspired by the "Puzzling Adventures" column in the December 2003 issue of Scientific American.

[Input]:

The input consists of one or more nonempty strings of at most 79 uppercase letters, each string on a line by itself, followed by a line containing only an asterisk that signals the end of the input.

[Output]:

For each string of letters, output whether or not it is surprising using the exact output format shown below.

[Sample Input]:

ZGBG
X
EE
AAB
AABA
AABB
BCBABCC
*

[Sample Output]:

ZGBG is surprising.
X is surprising.
EE is surprising.
AAB is surprising.
AABA is surprising.
AABB is NOT surprising.
BCBABCC is NOT surprising

解題思想：從要求來看，即定義D-pairs表示取字符串s中相距爲D的兩個字母所構成的字母對，該字母對中兩個字母的位置順序與他們在主串s中的位置順序一致定義D-unique表示，若從字符串s中取出所有相距爲D的字母對D-pairs，且這些D-pairs都是獨一無二的，那麼成字符串s是一個D-unique串D的取值範圍爲0~s.len()-2。然後這個用map的鍵值對來標記結果檢測時更爲方便。當然C的flag標記方式也可以，總的來說在大神看來是道簡單的poj題目。

souce_code: 

/*
 * =====================================================================================
 *
 *       Filename:  surprising_string.cpp
 *        Version:  1.0
 *        Created:  2013年10月13日 19時13分54秒
 *       Revision:  none
 *       Compiler:  g++
 *         Author:  szm
 *
 * =====================================================================================
 */

#include <iostream>
#include <string>
#include <map>
int main(int argc, char *argv[]){
	std::string s;
	while(std::getline(std::cin,s) && (s.c_str())[0]!='*'){
		if(s.size()<=2){
			std::cout<<s.c_str()<<" is surprising."<<std::endl;
			continue;
		}
		bool flag_final=true;
		for(int i=0;i<=(s.size()-2);i++){
			std::map<std::string,bool> mark;
			bool flag_unique=true;
			for(int j=0;j<=(s.size()-i-2);j++){
				char m_pair[3]={(s.c_str())[j],(s.c_str())[j+1+i],'\0'};
				std::string str(m_pair);
				if(!mark[str])
				      mark[str]=true;
				else{
					flag_unique=false;
					break;
				}
			}
			if(!flag_unique){
				flag_final=false;
				break;
			}
			mark.clear();
		}
		if(flag_final)
		      std::cout<<s<<" is surprising !"<<std::endl;
		else
		      std::cout<<s<<" is not surprising !"<<std::endl;
	}
	return 0;
}