Data Structures Algorithms MCQ (Multiple Choice Questions), Data Structures Algorithms Online Quiz

1 .

How is an array initialized in C language?

A)

int a[3] = {1, 2, 3};

B)

int a = {1, 2, 3};

C)

int a(3) = [1, 2, 3];

D)

int a[] = new int[3]

Correct Answer : Option (A) : int a[3] = {1, 2, 3};

2 .

Which of the following is a linear data structure?

A)

Array

B)

Graphs

C)

AVL Trees

D)

Binary Trees

Correct Answer : Option (A) : Array

3 .

Which data structure is mainly used for implementing the recursive algorithm?

A)

List

B)

Array

C)

Stack

D)

Queue

Correct Answer : Option (C) : Stack

4 .

What is the best time complexity we can achieve to precompute all-pairs shortest paths in a weighted graph?

A)

O(n)

B)

O(n^2)

C)

O(n^4)

D)

O(n^3)

Correct Answer : Option (D) : O(n^3)

5 .

What does the following code snippet do?

void dfs(int node, vector<vector<int>> &edges, vector<bool> &vis, vector<int> &dp) {
   vis[node] = true;
   for(auto x: edges[node]) {
       if(!vis[x]) {
           dp[x] = dp[node] + 1;
           dfs(x, edges, vis, dp);
       }
   }
}

A)

Finds the diameter of a tree.

B)

Counts the number of nodes in a given tree.

C)

Checks if all the nodes are reachable in a given tree.

D)

Stores depths of all the nodes in a given tree, with respect to some root node.

Correct Answer : Option (D) : Stores depths of all the nodes in a given tree, with respect to some root node.

6 .

A node in a tree, such that removing it splits the tree into forests, with size of each connected component being not greater than n / 2 is called?

A)

Path

B)

Centroid

C)

Center

D)

Diameter

Correct Answer : Option (B) : Centroid

7 .

What does the following code snippet calculate (edges represent the adjacency list representation of a graph)?

void solve(vector<vector<int>> edges) {
   int count = 0;
   for(auto x: edges) {
       for(auto y: x) {
           count += 1;
       }
   }
   cout << count / 2 << endl;
}

A)

Calculates the number of nodes in a given graph.

B)

Calculates the sum of degrees of all nodes in a given graph.

C)

Calculates the number of edges in an undirected graph.

D)

None of the above.

Correct Answer : Option (C) : Calculates the number of edges in an undirected graph.

8 .

Which of the following represents the Post order Traversal of a Binary Tree?

A)

Left -> Right -> Root

B)

Left -> Root -> Right

C)

Right -> Left -> Root

D)

Right -> Root -> Left

Correct Answer : Option (A) : Left -> Right -> Root

9 .

What is the information, which a LinkedList's Node must store?

A)

The value of the current node

B)

The address of the next node if it exists

C)

Both (A) and (B)

D)

None of the above

Correct Answer : Option (C) : Both (A) and (B)

10 .

How is the 2nd element in an array accessed based on pointer notation?

A)

*(a + 2)

B)

*a + 2

C)

&(a + 2)

D)

*(*a + 2)

Correct Answer : Option (A) : *(a + 2)