*[Lintcode]Simplify Path简化路径

Given an absolute path for a file (Unix-style), simplify it.

Example

"/home/"

, => 

"/home"

"/a/./b/../../c/"

, => 

"/c"

分析：用stack，先将路径split，得到的数组有几种字符需要处理 "."：代表当前目录，忽略  "../"：代表上一级目录，出栈, 其他：代表路径名称，入栈

最后拼接成新路径。注意split在匹配时会出现空字符串匹配。

public class Solution {
/**
* @param path the original path
* @return the simplified path
*/
public String simplifyPath(String path) {
Stack<String> stack = new Stack<String>();
String[] str = path.split("/");

//考虑/...
for(int i = 0; i < str.length; i++) {
if(str[i].equals(".")){

} else if(str[i].equals("..")) {
stack.pop();
} else {
stack.add(str[i]);
}
}
if(stack.isEmpty()) return "/";

StringBuilder sb = new StringBuilder();
while(!stack.isEmpty()) {
if(stack.peek().equals("")) stack.pop();
else sb.insert(0, "/" + stack.pop());
}

return sb.length() == 0 ? "/" : sb.toString();
}
}