旋转字符串的算法？

Question

虽然我真的只需要一个旋转算法，但字符串似乎是最容易做到的事情，虽然因为这不是任何特定语言所以它确实无关紧要。如何改变

ab
c

到

b
ac

Answer 1

有几种解决方案。 I guess this can give you an idea（C中的数组旋转解决方案）

这个使用字符

#include <stdio.h>
#include <string.h>

/* Left rotation of a string is to move some leading characters to its end, for example, if the input string is “abcdefg” and a number 2, two characters are rotated and the result
is “cdefgab”. */

void solution1(char *s, int n, int rotate) {
    char new_s[n * 2 + 1];
    strcpy(new_s, s);
    strcat(new_s, s);
    for (int i = 0; i < n; i++) /* extract s from "abcdeabcde" */
       s[i] = new_s[i + rotate];
    printf("%s\n", s);
}
/* solution 2*/
void reverse(char *s, char *start, char *end) {
    char temp;
    while (start < end) {
        temp = *start;
        *start = *end;
        *end = temp;
        start++;
        end--;
    }
}

void solution2(char *s, int length, int rotate) {
    char *first = s;
    char *first_end = s + rotate - 1;
    char *second = s + rotate;
    char *second_end = s + length - 1;
    if(s != NULL && length > 0 && rotate > 0 && rotate < length) {
    /* Reverse the n leading characters */
        reverse(s, first, first_end);
    /* Reverse other characters */
       reverse(s, second, second_end);
    /* Reverse the whole string */
       reverse(s, first, second_end);
    }
}

int main() {

    char s[8] = "abc";
    int n = (int) strlen(s);
    solution1(s, n, 2);
    printf("%s\n", s);
    solution2(s, n, 2);
    printf("%s\n", s);
    return 0;
}

此输出

sh-4.3#main 
cab
cab 
bca 

根据你想要的结果修改它应该不是那么复杂。