a situation that occurs when two distinct pieces of data have the same hash value, checksum, fingerprint, or cryptographic digest.
See also the hash wiki tag.
Questions tagged [hash-collision]
212 questions
0
votes
1 answer
Hashed array linked list collision resolution error
This block of code reads a dictionary file and stores it in a hashed array. This hashing array uses linked list collision resolution. But, for some incomprehensible reason, the reading stops in the middle. (i'm assuming some problem occurs when…
slow
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0
votes
10 answers
Chaining in HashMap
Code:
public static void main(String[] args) {
Map map= new HashMap();
map.put("a", "s");
map.put("a", "v");
System.out.println(map.get("a"));
}
Now, as per my understanding, since the key values in…
Kraken
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-1
votes
2 answers
How to check if there are collisions in C# Dictionary?
It's possible to get the map's bucket size in C++ to check the collision status but I couldn't find a way to do that in C#. How can I know if Dictionary has been collided?
I want to test my custom hashing function, because even though the function…
phuclv
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-1
votes
2 answers
Value modification of key-pair in HashMap and impact for a HashCode
A few days ago I had an interview and there a few interesting questions occurred. Namely, the recruiter asked me meticulous questions. Some of them concerned the close relationship between HashCode and the collections, which are based on the…
Martin
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-1
votes
1 answer
Dealing with python hash() collision
I've created a program to take a users predetermined unique identifier, hash it, and store it in a dictionary mapping to the user's name. I later receive the unique identifier, rehash it, and can look up the user's name.
I've come to a problem…
JamesRichardson
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-1
votes
1 answer
Will similar Strings in HashMap lead to increased chance of collisions?
Consider the following:
HashMap hm = new HashMap<>();
final String prefix = "My objects ";
int counter = 0;
void put(Object value) {
hm.put(prefix+(counter++), value);
}
Given that the key of each entry starts with the same…
Sina Madani
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-1
votes
1 answer
How to determine whether to overwrite a value or use a collision strategy? (Java HashMaps)
I have been implementing a hashmap from scratch and this dawned on me.
Lets say I have 3 distinct keys and 3 values
Keys -> Value: A -> 1, B -> 2,C -> 3
and they each land in an open slot in the array.
If the fourth key D produces the same…
Rstack
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-1
votes
2 answers
Hash Collisions even after overriding equals and hashcode methods for object being stored as key in Hashmap
I need to store object type of class edge as Key and ArrayList as Value
public class edge {
String edgeType; // Horizontal or Vertical edge
int i; //i and j for a cell in 2D matrix
int j;
}
HashMap>…
GagandeepR
- 1
- 1
-1
votes
1 answer
Hash table collision-handling schemes and the load factors
Which of the hash table collision-handling schemes could tolerate a load factor above 1 and which could not?
Thank you in advance!
CSstudent
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votes
1 answer
Reducing size of hash
If I have some data I hash with SHA256 like this :- hash=SHA256(data)
And then copy only the first 8 bytes of the hash instead of the whole 32 bytes, how easy is it to find a hash collision with different data? Is it 2^64 or 2^32 ?
If I need to…
Harry
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-1
votes
1 answer
How to generate random number without repetition in java using hash function
I want to add a shuffle option in my android music player app. For that purpose i am calling a random function in java to return a number between 0 and size of the currently playing songs list.
The problem is that the function returns same value as…
Shanij P.S
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- 8
-1
votes
1 answer
Collision generators or Datasets for hash collisions (like MD5, SHA-1 ...)
I'd like to test 3rd party (including "closed source") tools (like synchronization, de-duplication...) behaves in presence of files with same size and digest checksum (popular ones CRC32, MD5,SHA-1 ... etc).
Some of those hashing methods have known…
Grzegorz Wierzowiecki
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-2
votes
1 answer
go maps non-performant for large number of keys
I discovered very strange behaviour with go maps recently. The use case is to create a group of integers and have O(1) check for IsMember(id int).
The current implementation is :
func convertToMap(v []int64) map[int64]void {
out :=…
zaRRoc
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-2
votes
2 answers
Implementing HashMap: Avoid collisions caused by compress function
I'm implementing a hashmap to contain all words in a word file (e.g dictionary.txt, bible.txt) and I am having a collision problem. I know that there are many good hash functions out there but when I try compressing the hash code using this…
Mike Pham
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-2
votes
1 answer
Fast and (practically) collision free hash
I have an object which calculates a (long) path. Two objects are equal if the calculates the same path. I previously tested if two objects were equal by just doing something like:
obj1.calculatePath() == obj2.calculatePath()
However, now this has…
Markus
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