DP on Trees Diameter of Tree in DSA C - Interactive Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare the adjacency list for the tree.

DSA C

int adj[[1]][100]; // adjacency list for tree
int size[[1]]; // size of adjacency for each node

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A1000

B10000

C100

D10

Attempts:

3 left

💡 Hint

Common Mistakes

Choosing too small an array size causing out-of-bounds errors.

Choosing unnecessarily large arrays wasting memory.

The adjacency list size is set to 10000 to handle up to 10000 nodes, which is common for tree problems.

2fill in blank

medium

Complete the code to add an edge from node u to node v in the adjacency list.

DSA C

adj[u][size[u]++] = [1];

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Av

Bu

Csize[u]

Dsize[v]

Attempts:

3 left

💡 Hint

Common Mistakes

Adding u instead of v causing incorrect adjacency.

Using size[v] which is unrelated here.

We add node v to the adjacency list of node u, so the correct value is v.

3fill in blank

hard

Fix the error in the DFS function header to correctly pass the parent node.

DSA C

void dfs(int u, int [1]) {

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Aparent

Bpar

Cprev

Dp

Attempts:

3 left

💡 Hint

Common Mistakes

Using unclear or inconsistent parameter names.

Omitting the parent parameter causing infinite recursion.

Using 'parent' as the parameter name is clear and consistent with common tree DFS implementations.

4fill in blank

hard

Fill both blanks to update the diameter and height during DFS.

DSA C

if (height[v] + height[u] + 1 > diameter) {
    diameter = height[v] + height[u] + [1];
}
height[u] = 1 + [2];

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A1

B0

Cheight[v]

Ddiameter

Attempts:

3 left

💡 Hint

Common Mistakes

Forgetting to add 1 to diameter update.

Assigning height[u] without adding 1.

Add 1 for the edge between u and v to update diameter; height[u] is 1 plus the max height of child v.

5fill in blank

hard

Fill all three blanks to complete the DFS loop over children and update heights.

DSA C

for (int i = 0; i < size[u]; i++) {
    int v = adj[u][[1]];
    if (v != [2]) {
        dfs(v, u);
        if (height[v] > height[u]) {
            height[u] = height[v];
        }
    }
}
height[u] = height[u] + [3];

Drag options to blanks, or click blank then click option'

Ai

Bparent

C1

D0

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong index variable for adjacency.

Not skipping the parent node causing infinite recursion.

Forgetting to add 1 to height[u].

Loop index i is used to access adjacency; skip parent node; height[u] is incremented by 1 for edge.