UVa1584 Circular Sequence(环状序列) （java版本）

Some DNA sequences exist in circular forms as in the following figure, which shows a circular sequence ``CGAGTCAGCT", that is, the last symbol ``T" in ``CGAGTCAGCT" is connected to the first symbol ``C". We always read a circular sequence in the clockwise direction.

Since it is not easy to store a circular sequence in a computer as it is, we decided to store it as a linear sequence. However, there can be many linear sequences that are obtained from a circular sequence by cutting any place of the circular sequence. Hence, we also decided to store the linear sequence that is lexicographically smallest among all linear sequences that can be obtained from a circular sequence.

Your task is to find the lexicographically smallest sequence from a given circular sequence. For the example in the figure, the lexicographically smallest sequence is ``AGCTCGAGTC". If there are two or more linear sequences that are lexicographically smallest, you are to find any one of them (in fact, they are the same).

Input 

The input consists of T test cases. The number of test cases T is given on the first line of the input file. Each test case takes one line containing a circular sequence that is written as an arbitrary linear sequence. Since the circular sequences are DNA sequences, only four symbols, A, C, G and T, are allowed. Each sequence has length at least 2 and at most 100.

Output 

Print exactly one line for each test case. The line is to contain the lexicographically smallest sequence for the test case.

The following shows sample input and output for two test cases.

input

2                                     CGAGTCAGCT                            CTCC

output

AGCTCGAGTC 

CCCT

易错点：scanner除了nextLine方法外其它next方法都不会清除输入流中的'\n'，这会导致调用完其它next方法后流的开头剩一个'\n'而使得nextLine读入一个空串。要混用的时候最好检查nextLine读入的空串并重新读取

import java.util.Scanner;public class circular {public static void main(String[] args) {String s1="";Scanner in= new Scanner(System.in);int t=in.nextInt();in.nextLine();   //上一句读取之后加一个nextLine（）语句，将nextint（）之后按的换行回车过滤掉for(int q=0;q<t;q++){String s=in.nextLine();char[] c=s.toCharArray();int n=s.length();char[] c1 = new char[100];int ans=0;for(int i=0;i<n;i++){Boolean f=false;for(int j=0;j<n;j++){if (c[(ans+j)%n]>c[(i+j)%n]){f=true;break;}if (c[(ans+j)%n]<c[(i+j)%n]){break;}}if(f){ans=i;}}for(int p=0;p<n;p++){s1+=c[(p+ans)%n];}s1+="\n";}System.out.println(s1);}}