# Recent activity

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A Boolean expression is an expression made out of propositional letters (such as $p, q, r$) and operators $\wedge$, $\vee$ and $\neg$; e.g. $p\wedge \neg (q \vee \neg r)$. An expression is said to be in sum of product form ... operator. Every Boolean expression is equivalent to an expression without $\wedge$ operator. Every Boolean expression is equivalent to an expression without $\neg$ operator.
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Let $G_1 = (N, T, P, S_1)$ be a CFG where, $N=\{S_1, A, B\},T=\{a, b\}$ and $P$ ... $5$ production rules. Is $L_2$ inherently ambiguous?
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The less-than relation, $<,$ on reals is a partial ordering since it is asymmetric and reflexive a partial ordering since it is antisymmetric and reflexive not a partial ordering because it is not asymmetric and not reflexive not a partial ordering because it is not antisymmetric and reflexive none of the above
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Primary index vs Secondary Index Primary index is done on the primary key of the database.Secondary indexing is done on the candidate key..and clusterd index on non key field. Which indexing required dense and sparse indexing and why ? WHy cant secondary indices be done based on sparse indexing as it is order on candidate key and which also orders the file?
1 vote
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Consider the following four schedules due to three transactions (indicated by the subscript) using read and write on a data item $x$, denoted by $r(x)$ and $w(x)$respectively. Which one of them is conflict serializable? $r_1(x);r_2(x);w_1(x);r_3(x);w_2(x)$ $r_2(x);r_1(x);w_2(x);r_3(x);w_1(x)$ $r_3(x);r_2(x);r_1(x);w_2(x);w_1(x)$ $r_2(x);w_2(x);r_3(x);r_1(x);w_1(x)$ $1$ $2$ $3$ $4$
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A $3-\text{ary}$ tree is a tree in which every internal node has exactly three children. Use induction to prove that the number of leaves in a $3-\text{ary}$ tree with $n$ internal nodes is $2(n+1)$.
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Given the programming constructs assignment for loops where the loop parameter cannot be changed within the loop if-then-else forward go to arbitrary go to non-recursive procedure call recursive procedure/function call repeat loop, which constructs will you not include in a programming language such that it should be ... $\text{(vi), (vii), (viii)}$ $\text{(iii), (vii), (viii)}$
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The horse has played a little known but very important role in the field of medicine. Horses were injected with toxins of diseases until their blood built up immunities. Then a serum was made from their blood. Serums to fight with diphtheria and ... , that horses were given immunity to diseases generally quite immune to diseases given medicines to fight toxins given diphtheria and tetanus serums
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What is the chromatic number of an $n$ vertex simple connected graph which does not contain any odd length cycle? Assume $n > 2$. $2$ $3$ $n-1$ $n$
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Forty students watched films A, B and C over a week. Each student watched either only one film or all three. Thirteen students watched film A, sixteen students watched film B and nineteen students watched film C. How many students watched all three films? 0 2 4 8
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Given $\Sigma=\{a,b\}$, which one of the following sets is not countable? Set of all strings over $\Sigma$ Set of all languages over $\Sigma$ Set of all regular languages over $\Sigma$ Set of all languages over $\Sigma$ accepted by Turing machines
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The aim of the following question is to prove that the language $\{M \mid M$ $\text {is the code of the Turing Machine which, irrespective of the input, halts and outputs a}$ $1\}$, is undecidable. This is to be done by reducing from the language $\{M', x \mid M'$ ... what is the second step $M$ must make? What key property relates the behaviour of $M$ on $w$ to the behaviour of $M'$ on $x$?
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A multithreaded program $P$ executes with $x$ number of threads and uses $y$ number of locks for ensuring mutual exclusion while operating on shared memory locations. All locks in the program are non-reentrant, i.e., if a thread holds a lock $l$, then it cannot re-acquire lock $l$ without releasing it. If a thread is ... deadlock are: $x = 1, y = 2$ $x = 2, y = 1$ $x = 2, y = 2$ $x = 1, y = 1$
1 vote
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Consider a uniprocessor system with four processes having the following arrival and burst times: $\begin{array}{|c|c|c|l|} \hline&\text{Arrival Time}&\text{CPU Burst Time} \\ \hline P1&0&10\\P2&1&3\\P3&2.1&2\\P4&3.1&1 \\ \hline\end{array}$ Calculate the average waiting time ... $P4$, with CPU burst times of $2$ units each. In this case, what will be the turnaround time of $P1$? Justify your answer
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The preorder traversal sequence of a binary search tree is $30, 20, 10, 15, 25, 23, 39, 35, 42$. Which one of the following is the postorder traversal sequence of the same tree? $10, 20, 15, 23, 25, 35, 42, 39, 30$ $15, 10, 25, 23, 20, 42, 35, 39, 30$ $15, 20, 10, 23, 25, 42, 35, 39, 30$ $15, 10, 23, 25, 20, 35, 42, 39, 30$
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The head of a hard disk serves requests following the shortest seek time first (SSTF) policy. The head is initially positioned at track number $180$. Which of the request sets will cause the head to change its direction after servicing every request assuming that the head does not change direction if there ... $10, 139, 169, 178, 181, 184, 201, 265$ $10, 138, 170, 178, 181, 185, 200, 265$
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Consider a TCP client and a TCP server running on two different machines. After completing data transfer, the TCP client calls close to terminate the connection and a FIN segment is sent to the TCP server. Server-side TCP responds by sending an ACK, which is received by the ... does the client-side TCP connection wait for the FIN from the server-side TCP? LAST-ACK TIME-WAIT FIN-WAIT-1 FIN-WAIT-2
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Consider the following Boolean expression. $F=(X+Y+Z)(\overline X +Y)(\overline Y +Z)$ Which of the following Boolean expressions is/are equivalent to $\overline F$ (complement of $F$)? $(\overline X +\overline Y +\overline Z)(X+\overline Y)(Y+\overline Z)$ $X\overline Y + \overline Z$ $(X+\overline Z)(\overline Y +\overline Z)$ $X\overline Y +Y\overline Z + \overline X \overline Y \overline Z$
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(a) Suppose you are given an empty B+- tree where each node (leaf and internal) can store up to 5 key values. Suppose values 1, 2,.....10 are inserted, in order, into the tree. Show the tree pictorially after 6 insertions, and after all 10 insertions Do NOT ... . Then what approximately is the average number of keys in each leaf level node. in the normal case, and with the insertion as in (b).
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Consider the following statements: The smallest element in a max-heap is always at a leaf node The second largest element in a max-heap is always a child of a root node A max-heap can be constructed from a binary search tree in $\Theta(n)$ time A binary search tree can be constructed ... time Which of te above statements are TRUE? I, II and III I, II and IV I, III and IV II, III and IV
Consider a complete binary tree with $7$ nodes. Let $A$ denote the set of first $3$ elements obtained by performing Breadth-First Search $\text{(BFS)}$ starting from the root. Let $B$ denote the set of first $3$ elements obtained by performing Depth-First Search $\text{(DFS)}$ starting from the root. The value of $\mid A-B \mid$ is _____________
The network $198.78.41.0$ is a : Class A Network Class B Network Class C Network Class D Network
Consider the following $\text{C}$ program: #include<stdio.h> int counter=0; int calc (int a, int b) { int c; counter++; if(b==3) return (a*a*a); else { c = calc(a, b/3); return (c*c*c); } } int main() { calc(4, 81); printf("%d", counter); } The output of this program is ______.