My algorithm can find duplicate files comparing items one by one in the list.
For example, a list with 5 items:
if position[0] is equal to position[1], [2], [3], [4]
if position[1] is equal to position[0], [2], [3], [4]
if position[2] is equal to position[0], [1], [3], [4]
if position[3] is equal to position[0], [1], [2], [4]
if position[4] is equal to position[0], [1], [2], [3]
So imagine a list of 3000 items, it really takes several minutes.
//pathList is an arraylist list of all files path of a specific folder
for (int pos = 0; pos < pathList.size(); pos++) {
for (int i = 0; i < pathList.size(); i++) {
if (pos != i) {
if (FilesAreEqual(new File(pathList.get(pos)), new File(pathList.get(i)))) {
if (!mDuplicateList.contains(pathList.get(pos)) &&
!mDuplicateList.contains(pathList.get(i)))
mDuplicateList.add(pathList.get(i));
}
}
}
}
pathList.remove(pos);
}
Even comparing file size first, it's still slow
boolean FilesAreEqual(File file1, File file2) {
if (file1.length() != file2.length()) return false;
try {
if (!FileUtils.contentEquals(file1, file2)) return false;
} catch (IOException e) {
e.printStackTrace();
return false;
}
return true;
}
I want to do it faster, like some Play Store apps. I have no idea how they can scan more than 15000 files in seconds.
Can you tell me a way to scan a folder very fast like those apps or help me to improve my algorithm ?
