leetcode simplify-path-优快云博客

本文链接：https://blog.youkuaiyun.com/pynash123/article/details/84572376

本文提供了一种简化Unix风格文件路径的方法，通过去除多余的符号和层级，将路径转换为规范形式。重点介绍了如何处理特殊符号如'..'和'.'，并给出了详细的实现代码。

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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".

class Solution {
public:
    string simplifyPath(string path) 
    {
        string res("");
        for (int i=0;i<path.size();i++)
        {
            if (path[i] == '/')
            {
                if(i == path.size()-1)
                    break;
                if(path[i+1] == '/')  //  //
                    continue;
                int pos = Find(path, i+1);
                string tmp = path.substr(i+1, pos-i-1);
                string str1("..");
                string str2(".");
                if (tmp== str1)//  /..
                {
                    i += 2;
                    int tmp = res.rfind('/');
                    if (string::npos != tmp)
                        res.erase(res.begin()+tmp, res.end());
                }
                else if (tmp== str2)//  /.
                {
                    ++i;
                    continue;
                }
                else
                {
                    res += path[i++];
                    while(i<path.size() && path[i] != '/')
                    {
                        res += path[i++];
                    }
                    --i;
                }
            }
        }
        if (0 == res.size())
            res += '/';
        return res;
    }
    int Find(string path, int start)
    {
        string s = path.substr(start);
        int tmp = s.find('/');
        if (string::npos == tmp)
            return path.size();
        return tmp + start;
    }
};

class Solution {
public:
    string simplifyPath(string path) 
    {
        string res("");
        int i=0;
        while (i<path.size())
        {
            while (path[i] == '/' && i < path.size()) ++i;
            if(i == path.size())
                break;
            int start = i;
            while (path[i] != '/' && i < path.size()) ++i;
            int end = i-1;
            string tmp = path.substr(start, end - start + 1);
            if (tmp== "..")//  /..
            {
                int tmp = res.rfind('/');
                if (string::npos != tmp)
                    res.erase(res.begin()+tmp, res.end());
            }
            else if (tmp != ".")//  /.
            {
                res += '/';
                res += tmp;
            }
        }
        return res.empty()?"/":res;
    }
};

测试

#include<iostream>
#include<string>
using namespace std;



class Solution1 {
public:
    string simplifyPath(string path) 
    {
        string res("");
        for (int i=0;i<path.size();i++)
        {
            if (path[i] == '/')
            {
                if(i == path.size()-1)
                    break;
                if(path[i+1] == '/')  //  //
                    continue;
                int pos = Find(path, i+1);
                cout<<"pos :"<<pos<<" i :"<<i<<endl;
                string tmp = path.substr(i+1, pos-i-1);
                cout<<"tmp :"<<tmp<<endl;
                string str1("..");
                string str2(".");
                if (tmp== str1)//  /..
                {
                    int tmp = res.rfind('/');
                    if (string::npos != tmp)
                        res.erase(res.begin()+tmp, res.end());
                }
                else if (tmp== str2)//  /.
                {
                    continue;
                }
                else
                {
                    res += path[i++];
                    while(i<path.size() && path[i] != '/')
                    {
                        res += path[i++];
                    }
                    --i;
                }
            }
        }
        if (0 == res.size())
            res += '/';
        return res;
    }
    int Find(string path, int start)
    {
        string s = path.substr(start);
        int tmp = s.find('/');
        if (string::npos == tmp)
            return path.size();
        return tmp + start;
    }
};

class Solution {
public:
    string simplifyPath(string path) 
    {
        string res("");
        int i=0;
        while (i<path.size())
        {
            cout<<" i :"<<i<<endl;
            while (path[i] == '/' && i < path.size()) ++i;
            if(i == path.size())
                break;
            int start = i;
            while (path[i] != '/' && i < path.size()) ++i;
            int end = i-1;
            string tmp = path.substr(start, end - start + 1);
            if (tmp== "..")//  /..
            {
                int tmp = res.rfind('/');
                if (string::npos != tmp)
                    res.erase(res.begin()+tmp, res.end());
            }
            else if (tmp != ".")//  /.
            {
                res += '/';
                res += tmp;
            }
        }
        return res.empty()?"/":res;
    }
};

int main()
{
    Solution s;
    string str("/../");
    cout<<s.simplifyPath(str)<<endl;
}