Circular Sequence(UVa 1584)

Circular Sequence

Time Limit: 3000ms

Memory Limit: Unknown KB
This problem will be judged on UVALive.
Original ID: 3225

64-bit integer IO format: %lld     
Java class name: Main

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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.

Sample Input 

2
CGAGTCAGCT
CTCC

代码分析：用s[(p+i)%n]实现数组的循环遍历

#include<stdio.h>
#include<string.h>
#define MAXN 105

//s环的P方法是否小于q方法
int less(const char* s,int p,int q)
{
int n = strlen(s);
for(int i=0; i<n; i++)
{
if(s[(p+i)%n] < s[(q+i)%n]) return 1;
else if(s[(p+i)%n] > s[(q+i)%n]) return 0;
}
}

int main()
{
int T;
char s[MAXN];

scanf("%d", &T);

while(T--)
{
scanf("%s", s);
int ans = 0;
int n = strlen(s);
for(int i=0; i<n; i++)
if(less(s, i, ans)) ans = i;

for(int i=0; i<n; i++)
putchar(s[(i+ans)%n]);

putchar('\n');
}
return 0;
}

Sample Output 

AGCTCGAGTC
CCCT