# Recent questions tagged hashing

In Mid Square Method(Hashing), we square the given number and then use appropriate bits from the middle. Can we have so many answers for a particular question? On what basis we choose the middle digit? What if the square is 4 digit 1234, then what will be the middle value? Will it be 23 or 2 or 3. Please explain.
Consider a $\textit{dynamic}$ hashing approach for $4$-bit integer keys: There is a main hash table of size $4$. The $2$ least significant bits of a key is used to index into the main hash table. Initially, the main hash table entries are empty. Thereafter, when more keys are hashed into it, to resolve ... in decimal notation)? $5,9,4,13,10,7$ $9,5,10,6,7,1$ $10,9,6,7,5,13$ $9,5,13,6,10,14$
" if we assume uniform hashing, what is the probability that a collision will occur in a hash table with 100 buckets and 2 keys?" Doesn't this question means that we have a hash table in which there are already 2 keys, and we have to find probability of collision for the next insertion? Or it is asking the probability of collision in the table for these two keys insertion?
https://gateoverflow.in/57653/cormen-2nd-edition-exercise-11-2-1 WHY WE CANT DO LIKE THIS …...NUMBER OF COLLISIONS(X) : 0 1 2 3 4 …………………...N-1 P(X): 0/M 1/M 2/M…………………… … ………….(N-1)/M
A hash table of length $10$ uses open addressing with hash function $h(k) = k \: mod \: 10$, and linear probing. After inserting $6$ ... insertion sequences of the key values using the same hash function and linear probing will result in the hash table shown above? $10$ $20$ $30$ $40$
A hash table with ten buckets with one slot per bucket is shown in the following figure. The symbols $S1$ to $S7$ initially entered using a hashing function with linear probing. The maximum number of comparisons needed in searching an item that is not present is $4$ $5$ $6$ $3$
Consider a hash function that distributes keys uniformly. The hash table size is $20$. After hashing of how many keys will the probability that any new key hashed collides with an existing one exceed $0.5$. $5$ $6$ $7$ $10$
Consider a hash table with $100$ slots. Collisions are resolved using chaining. Assuming simple uniform hashing, what is the probability that the first $3$ slots are unfilled after the first $3$ insertions? $(97 \times 97 \times 97) / 100^3$ $(99 \times 98 \times 97) / 100^3$ $(97 \times 96 \times 95) / 100^3$ $(97 \times 96 \times 95 / (3! \times 100^3)$
Which one of the following hash functions on integers will distribute keys most uniformly over $10$ buckets numbered $0$ to $9$ for $i$ ranging from $0$ to $2020$? $h(i) = i^2 \text{mod } 10$ $h(i) = i^3 \text{mod } 10$ $h(i) = (11 \ast i^2) \text{mod } 10$ $h(i) = (12 \ast i^2) \text{mod } 10$
An advantage of chained hash table (external hashing) over the open addressing scheme is Worst case complexity of search operations is less Space used is less Deletion is easier None of the above
Consider a hash table with $n$ buckets, where external (overflow) chaining is used to resolve collisions. The hash function is such that the probability that a key value is hashed to a particular bucket is $\frac{1}{n}$. The hash table is initially empty and $K$ ... has occurred in any of the $K$ insertions? What is the probability that the first collision occurs at the $K^{th}$ insertion?
Consider a hash table of size seven, with starting index zero, and a hash function $(3x + 4)\mod 7$. Assuming the hash table is initially empty, which of the following is the contents of the table when the sequence $1, 3, 8, 10$ is inserted into the table using closed hashing? Note that − denotes an empty location in the ... $3$ $1$, −, −, −, −, −, $3$ $1, 10, 8$, −, −, −,$3$
Which of the following statements is true? As the number of entries in a hash table increases, the number of collisions increases. Recursive programs are efficient The worst case complexity for Quicksort is $O(n^2)$ Binary search using a linear linked list is efficient I and II II and III I and IV I and III
Consider a hash table with $9$ slots. The hash function is $h(k)= k \mod 9$. The collisions are resolved by chaining. The following $9$ keys are inserted in the order: $5, 28, 19, 15, 20, 33, 12, 17, 10$. The maximum, minimum, and average chain lengths in the hash table, respectively, are $3, 0,$ and $1$ $3, 3,$ and $3$ $4, 0,$ and $1$ $3, 0,$ and $2$
A hash table of length $10$ uses open addressing with hash function $h(k) = k \mod 10$, and linear probing. After inserting $6$ ... $46, 42, 34, 52, 23, 33$ $34, 42, 23, 52, 33, 46$ $46, 34, 42, 23, 52, 33$ $42, 46, 33, 23, 34, 52$
Insert the characters of the string $K \ R \ P \ C \ S \ N \ Y \ T \ J \ M$ into a hash table of size $10$. Use the hash function $h(x)=( ord (x) – ord ("a") + 1) \mod 10$ and linear probing to resolve collisions. Which insertions cause collisions? Display the final hash table.
A hash table contains $10$ buckets and uses linear probing to resolve collisions. The key values are integers and the hash function used is key % $10$. If the values $43, 165, 62, 123, 142$ are inserted in the table, in what location would the key value $142$ be inserted? $2$ $3$ $4$ $6$
Given that hash table $T$ with $25$ slots that stores $2000$ elements, the load factor $a$ for $T$ is _________.
Which of the following statement(s) is TRUE? A hash function takes a message of arbitrary length and generates a fixed length code. A hash function takes a message of fixed length and generates a code of variable length. A hash function may give the same hash value for distinct messages. I only II and III only I and III only II only
The keys $12, 18, 13, 2, 3, 23, 5$ and $15$ are inserted into an initially empty hash table of length $10$ using open addressing with hash function $h(k) = k \mod 10$ ...
1 vote
Consider a double hashing scheme in which the primary hash function is $h_1(k)= k \text{ mod } 23$, and the secondary hash function is $h_2(k)=1+(k \text{ mod } 19)$. Assume that the table size is $23$. Then the address returned by probe $1$ in the probe sequence (assume that the probe sequence begins at probe $0$) for key value $k=90$ is_____________.
Given the following input $(4322, 1334, 1471, 9679, 1989, 6171, 6173, 4199)$ and the hash function $x$ mod $10$, which of the following statements are true? $9679, 1989, 4199$ hash to the same value $1471, 6171$ hash to the same value All elements hash to the same value Each element hashes to a different value I only II only I and II only III or IV
Consider a hash table of size $11$ that uses open addressing with linear probing. Let $h(k) = k \mod 11$ be the hash function used. A sequence of records with keys $43 \ 36 \ 92 \ 87 \ 11 \ 4 \ 71 \ 13 \ 14$ is inserted into an initially empty hash table, the bins of which are indexed from zero to ten. What is the index of the bin into which the last record is inserted? $3$ $4$ $6$ $7$
Consider a hash table with chaining scheme for overflow handling: What is the worst-case timing complexity of inserting $n$ elements into such a table? For what type of instance does this hashing scheme take the worst-case time for insertion?
In hashing, collision resolution is carried out by close addressing. Which of the following is close addressing technique – I. Buckets (for contiguous storage) II. Chains (for linked storage) A. Only I B. Only II C. I and II D. None i think Buckets for continuous storage is like arrays so it will use linear probing (open addressing) chains – uses closed addressing.
1 vote
Sequentially means one after another,there may or maynot gap between two, right?? Then how $m^{2}$ should be in denominator ?? What will be ans here, B) or C)??
Identify valid hash function for storing in the address range $\mathbf{1}$ to $\mathbf{1000}$ $\mathbf{h(x) = x \;mod\;1000}$ $\mathbf{(x+1)\;mod\;1000}$ $\mathbf{h(x) = x \;mod\;(1000+1)}$ $\mathbf{h(x) = (x \;mod\;1000)+1}$ My Work: According to me answer is $\mathbf{1}$ but the given answer is $\mathbf{4}$