【第三轮】6.16-6.22 CareerCup 1.2

【解题思路】Calculate the length of the string N('\0' excluded), then swap the str[0] and str[N-1], str[1] and str[N-2], ...
【时间复杂度】
O(n)
【空间复杂度】
O(1)
【gist link】
https://gist.github.com/nealhu/15b80e2e3224e30127a0

【解题思路】swap ith char and (len-i-1)th char
【时间复杂度】O(N)
【空间复杂度】O(1)
【gist link】https://gist.github.com/larry-liu/9d0e06ea7f6761fd32ee
---------------OPTional，如果觉得test case比较好，欢迎写出来分享----------------------
【test case】
str = malloc(256);
strcpy(str, "this is my test case");

I am not sure how to reply.... So I just write here.
It is only allowed in C99 mode to declare varible in for loop. To avoid that error message, I declare this i out of for loop.
Thanks for your reply and I think i need to compile my code in C99 mode.

readman 发表于 2014-6-16 00:07
【解题思路】
same to binary search ?
【时间复杂度】

求解释：为什么空间是lgN? 和binary search有什么关系？
评论：
  if (str[i] != str[j]) {
                swap(str, i , j);
            } 这个优化很不错

啊才通过，ignore这楼

【解题思路】reverse by tracking two index pointers
【时间复杂度】O(n)
【空间复杂度】O(1)
【gist link】https://gist.github.com/chrislukkk/30dcfb00ced279778de8

【解题思路】I just use str.toCharArray() to convert string to char[], and get char[]'s head and tail. Then swap head++ and tail-- char until they meet together. Finally, use String.valueOf(char[] str) to convert char[] to string
【时间复杂度】
O(n)
【空间复杂度】
O(1)
【gist link】https://gist.github.com/bindai/cecfc39649fade0b5718
求解： 为啥 我的 link 没有超链接

heycinderella 发表于 2014-6-18 11:02
求解释：为什么空间是lgN? 和binary search有什么关系？
评论：
  if (str != str[j]) {

..脑抽了..不好意思...
感觉和二叉搜索很像啊,

【解题思路】swap the first and last "char" in the "char * str" until the center of the string.
【时间复杂度】O(n)
【空间复杂度】O(1)
【gist link】https://gist.github.com/southpenguin/398170b101620d9c76f2

【解题思路】得到字符串长度L，第i个字符和L-i个字符进行交换。
【时间复杂度】O(n)
【空间复杂度】O(n)
【gist link】https://gist.github.com/guchang/2cf5ea70a893d0a118dd

【解题思路】Firstly get the length of the string. and then swap the i and length-i-1 characters. But I forgot that there is a function named strlen() can get the string length. and I write that function by myself. ++!
【时间复杂度】O(n)
【空间复杂度】O(1)
【gist link】https://gist.github.com/ZhuGuanyu/83c1aedc0a485fd96d06