Given an absolute path for a file (Unix-style), simplify it. Or in other words, convert it to the canonical path.
In a UNIX-style file system, a period . refers to the current directory. Furthermore, a double period .. moves the directory up a level. For more information, see: Absolute path vs relative path in Linux/Unix
Note that the returned canonical path must always begin with a slash /, and there must be only a single slash / between two directory names. The last directory name (if it exists) must not end with a trailing /. Also, the canonical path must be the shortest string representing the absolute path.
Example 1:
Input: "/home/"
Output: "/home"
Explanation: Note that there is no trailing slash after the last directory name.
Example 2:
Input: "/../"
Output: "/"
Explanation: Going one level up from the root directory is a no-op, as the root level is the highest level you can go.
Example 3:
Input: "/home//foo/"
Output: "/home/foo"
Explanation: In the canonical path, multiple consecutive slashes are replaced by a single one.
Example 4:
Input: "/a/./b/../../c/"
Output: "/c"
Example 5:
Input: "/a/../../b/../c//.//"
Output: "/c"
Example 6:
Input: "/a//b////c/d//././/.."
Output: "/a/b/c"题目链接：https://leetcode.com/problems/simplify-path/
我刚开始的想法：没有想到路径里可以包含 ...,所以我是一个一个字符处理，用例过了
| 240 / 254 test cases passed. |
最后我屈服了，这种方法行不通，但是代码留下，这个代码思路很奇特好吧
class Solution {
public:
string simplifyPath(string path) {
stack<char> stk;
string res="";
int len=path.length();
for(int i=0;i<len;i++)
{
//cout<<"he";
if(path[i]=='/')
{
if(!stk.empty()&&stk.top()=='/')//使用top(),一定要确认stk是否为空
{
}
else
{
stk.push('/');
}
}
else
{
if(path[i]=='.')
{
if(stk.top()=='.')
{
while(stk.top()!='/')
{
stk.pop();
}
stk.pop();
if(stk.empty())
{
stk.push('/');
}
}
else
{
while(stk.top()!='/')
{
stk.pop();
}
stk.pop();
if(stk.empty())
{
stk.push('/');
}
}
}
else
{
stk.push(path[i]);
}
}
}
if(stk.size()!=1&&stk.top()=='/')
stk.pop();
while(!stk.empty())
{
res=stk.top()+res;
stk.pop();
}
return res;
}
};贴上正确的代码
class Solution {
public:
string simplifyPath(string path) {
istringstream ss(path);
string tempPath;
vector<string> stack;
while(getline(ss,tempPath,'/')){
if(tempPath == "." || tempPath.empty()){
continue;
}else if(tempPath == ".."){
if(stack.empty() == false)
stack.pop_back();
}else{
stack.push_back(tempPath);
}
}
string result;
for(auto &s : stack){
result += "/" + s;
}
return result.empty() ? "/" : result;
}
};