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To find duplicate files by their content, we can use a HashMap (or Dictionary). For each directory info string, parse the directory path and the files with their contents. Use the content as the key in the map and store full path of the file as its value. After parsing all inputs, the map keys with more than one value represent duplicate files.
Time Complexity: O(n), where n is the total number of characters in all file paths. We iterate over each character once.
Space Complexity: O(n) to store the lists of file paths in the dictionary.
1import java.util.*;
2
3public class DuplicateFiles {
4 public List<List<String>> findDuplicate(String[] paths) {
5 Map<String, List<String>> contentMap = new HashMap<>();
6 for (String path : paths) {
7 String[] parts = path.split(" ");
8 String root = parts[0];
9 for (int i = 1; i < parts.length; i++) {
10 String[] nameContent = parts[i].split("\\(");
11 String name = nameContent[0];
12 String content = nameContent[1].substring(0, nameContent[1].length() - 1);
13 contentMap.computeIfAbsent(content, k -> new ArrayList<>()).add(root + "/" + name);
14 }
15 }
16 List<List<String>> result = new ArrayList<>();
17 for (List<String> group : contentMap.values()) {
18 if (group.size() > 1) {
19 result.add(group);
20 }
21 }
22 return result;
23 }
24}In Java, we use a HashMap to collect file paths by their content. Using the split method, we separate the root directory from the files. In a loop, the file name and contents are isolated, enabling us to map the full path of each file under its content as a key. Finally, groups with more than one entry are added to the result list and returned.
This approach is based on directly processing string data and arranging results using a 2D array. Strings are manipulated to extract directory data, file names, and contents into standalone variables, then append paths to a growing structure. Compared to hash maps, this method uses arrays to aggregate identical files.
Time Complexity: O(n), where n is the total input character count due to one-pass evaluation.
Space Complexity: O(n), maintaining paths and intermediate arrays.
1using System;
2using System.Collections.Generic;
public class DuplicateWithArrays
{
public IList<IList<string>> FindDuplicate(string[] paths)
{
Dictionary<string, List<string>> contentMap = new Dictionary<string, List<string>>();
foreach (string path in paths)
{
string[] parts = path.Split(' ');
string directory = parts[0];
for (int i = 1; i < parts.Length; i++)
{
int openParenIndex = parts[i].IndexOf('(');
int closeParenIndex = parts[i].IndexOf(')', openParenIndex);
string name = parts[i].Substring(0, openParenIndex);
string content = parts[i].Substring(openParenIndex + 1, closeParenIndex - openParenIndex - 1);
if (!contentMap.ContainsKey(content))
{
contentMap[content] = new List<string>();
}
contentMap[content].Add(directory + "/" + name);
}
}
var result = new List<IList<string>>();
foreach (var pair in contentMap)
{
if (pair.Value.Count > 1)
{
result.Add(pair.Value);
}
}
return result;
}
}Utilizing C#'s native string capabilities, this implementation deliberately processes content without relying on heavy structuring, using simple substring and index functions to group matching file paths by their contents.