题目：

解题思路：

        字符串拼接，先遍历复制从下标为 target 开始的 len - target 位字符，再遍历复制前 target位字符至末尾。

char* dynamicPassword(char* password, int target) {int len = strlen(password);// int num = 0;int i = 0;char* result = (char*) malloc(sizeof(char) * (len+1));for (; i+target < len; i++) {result[i] = password[i+target];}for (int j = 0; j < target; j++) {result[i] = password[j];i++;}result[i] = '\0';return result;
}