leetcode || 71、Simplify Path

problem：

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

path =

"/home/"

, =>

"/home"

path =

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

, =>

"/c"

click to show corner cases.
Corner Cases:

Did you consider the case where path =

"/../"

?

In this case, you should return

"/"

.
Another corner case is the path might contain multiple slashes

'/'

together,
such as

"/home//foo/"

.

In this case, you should ignore redundant slashes and return

"/home/foo"

.

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Stack String

题意：简化Unix风格路径

thinking：

提示使用stack来做

code：

class Solution {
public:
string simplifyPath(string path) {
stack<string> s;
string str;
for(int i = 0; i < path.size(); i++)
{
if (path[i] == '/')
{
if (str == "..")
{
if (!s.empty())
s.pop();
}
else if (str != "." && str != "")
{
s.push(str);
}

str = "";
}
else
{
str += path[i];
}
}

if (str == "..")
{
if (!s.empty())
s.pop();
}
else if (str != "." && str != "")
s.push(str);

if (s.empty())
return "/";

string ret;
while(!s.empty())
{
ret = "/" + s.top() + ret;
s.pop();
}

return ret;
}
};