Tag File system

Absolute Path Of A Targeted File Where The Virus Is Not Present!!

Arunima Mandal Leave a comment

Problem: https://domjudge.cs.fsu.edu/public/problems/13/text

Note:

This problem intuitively resembles a tree structure. But it can be solved using a deque easily, though I think the first data structure that will come to mind is a stack, at least that was in my case. A stack would work, but eventually while accessing all the elements of the stack for length counting, then you will get how deque will serve in that case!

In the following code, there are two limiting criteria:

One is that the length of the level cannot be less than the size of the deque, if it is greater then we have already processed the subdirectory/file and we haven’t found our answer yet, so we can discard that from the deque.

And the second one is the case of checking the virus file. If the virus file is found once, then even if we get our targeted file in the same hierarchy level or in any deeper level of the same root directory, we’ll have to discard it. We have handled this checking using two variables vi and vi_level. One can use 1 variable only instead of these two to check this.

Code:

#include <bits/stdc++.h>

using namespace std;

int main()
{
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);

    string target;
    cin>>target;
    string str,s,ss, ext;
    while(cin>>str)
    {
        s+=str;
        s+="\n";
    }
    int level=0, vi_level=0;
    bool flag=0, vi=0;
    deque<string> dq;

    for(int i=0; i<s.size(); i++)
    {
        if(s[i]=='\n')
        {
            dq.push_back(ss);
            if(flag)
            {
                if(ss==target)
                {
                    cout<<dq[0];
                    for(int i=1; i<dq.size(); i++) cout<<"/"<<dq[i];
                    return 0;
                }
                else if(ext=="virus")
                {
                    vi=1;
                    vi_level=level;
                }
            }
            ss.clear();
            level=0;
            flag=0;
            ext.clear();
        }
        else if(s[i]=='-') level++;
        else if(s[i]=='.')
        {
            if(vi && level>=vi_level) continue;
            ss+=s[i];
            flag=1;
        }
        else
        {
            if(level==0) vi=0;
            if(vi && level>=vi_level) continue;
            ss+=s[i];
            if(flag) ext+=s[i];
            while(level<dq.size()) dq.pop_back();
        }
    }
    return 0;
}

Print the Absolute File Path Of A Targeted File in C++

Arunima Mandal Leave a comment

Problem Statement: Given a file system(consisting of directories, sub-directories, and files) and a target file name, print the absolute path of that targeted file.

Input: Input would be a series of strings. The first line would be the target file name. From the next line onward, there will be multiple directories/sub-directories and file names separated by newlines. And “-” indicates the level hierarchy of each sub-directory or file. Assume that, the targeted file will always be present and will be unique in the input.

Output:

Print the path starting from the root directory name. Put a “/” in between directories, sub-directories, and files while printing the path.

Sample Input:

yes.cpp
Documents
-Homework
–DS.virus
–algo.docx
-yes.cpp
Downloads
-write.cpp
-yes.h

Sample Output:

Documents/yes.cpp

Code:

#include <bits/stdc++.h>

using namespace std;

int main()
{
    freopen("in.txt","r",stdin);
    freopen("out.txt","w",stdout);

    string target;
    cin>>target;
    string str,s,ss, ext;
    while(cin>>str)
    {
        s+=str;
        s+="\n";
    }
    int level=0;
    bool flag=0;
    deque<string> dq;

    for(int i=0; i<s.size(); i++)
    {
        if(s[i]=='\n')
        {
            dq.push_back(ss);
            if(flag && ss==target)
            {
                cout<<dq[0];
                for(int i=1; i<dq.size(); i++) cout<<"/"<<dq[i];
                return 0;
            }
            ss.clear();
            flag=0;
            level=0;
        }
        else if(s[i]=='-') level++;
        else if(s[i]=='.')
        {
            ss+=s[i];
            flag=1;
        }
        else
        {
            ss+=s[i];
            while(level<dq.size()) dq.pop_back();
        }
    }
    return 0;
}

LeetCode 388. Longest Absolute File Path

Arunima Mandal 1 Comment

Problem Link: https://leetcode.com/problems/longest-absolute-file-path/

Note:
This problem intuitively resembles a tree structure. But it can be solved using a deque easily, though I think the first data structure that will come to mind is a stack, at least that was in my case. A stack would work, but eventually while accessing all the elements of the stack for length counting, then you will get how deque will serve in that case!

In the following code, one limiting criterion is that the length of the level cannot be less than the size of the deque, if it is greater then we have already processed the subdirectory/file and we haven’t found our answer yet, so we can discard that from the deque. 

class Solution {
public:
    int lengthLongestPath(string input) {
        deque<int> dq;
        int len=0, level=0, res=0;
        bool flag=0;
        for(int i=0; i<input.size(); i++)
        {
            if(input[i]=='\n')
            {
                dq.push_back(len);
                len=0;
                level=0;
                flag=0; 
            }
            else if(input[i]=='\t') level++;
            else if(input[i]=='.')
            {
                flag=1;
                len++;
            }
            else
            {
                len++;
                if(flag)
                {
                    int sum=0;
                    for(int i=0; i<dq.size(); i++)
                    {
                        sum+=dq[i];
                    }
                    res=max(res, sum+len+level);
                }
                while(level<dq.size()) dq.pop_back();
            }
        }
        return res;
    }
};