Why Hash Map Exists and What Problem It Solves in DSA C - Test Your Knowledge

Practice - 5 Tasks

1fill in blank

easy

Complete the code to declare a hash map that stores integer keys and values.

DSA C

typedef struct {
    int key;
    int value;
} HashMapEntry;

HashMapEntry map[[1]];

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

Ahash

Bkey

C100

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Using variable names instead of a number for array size.

Confusing key or value with size.

The hash map is declared as an array of entries with a fixed size, here 100.

2fill in blank

medium

Complete the code to compute the hash index for a given key.

DSA C

int hashFunction(int key) {
    return key [1] 100;
}

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A%

B*

C+

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using multiplication or addition instead of modulo.

Not limiting the index within array bounds.

The modulo operator (%) is used to ensure the hash index fits within the array size.

3fill in blank

hard

Fix the error in the code that inserts a key-value pair into the hash map.

DSA C

void insert(HashMapEntry map[], int key, int value) {
    int index = hashFunction(key);
    map[index].key = key;
    map[index].[1] = value;
}

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Ahash

Bkey

Cindex

Dvalue

Attempts:

3 left

💡 Hint

Common Mistakes

Assigning to the key field instead of value.

Using wrong field names.

The value field of the map entry must be assigned the given value.

4fill in blank

hard

Fill both blanks to complete the code that retrieves a value by key from the hash map.

DSA C

int getValue(HashMapEntry map[], int key) {
    int index = hashFunction(key);
    if (map[index].key == [1]) {
        return map[index].[2];
    }
    return -1; // not found
}

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

Akey

Bvalue

Cindex

Dhash

Attempts:

3 left

💡 Hint

Common Mistakes

Comparing with wrong variable.

Returning the key instead of value.

Check if the stored key matches the requested key, then return the stored value.

5fill in blank

hard

Fill all three blanks to complete the code that handles collision by linear probing in the hash map insertion.

DSA C

void insert(HashMapEntry map[], int key, int value) {
    int index = hashFunction(key);
    while (map[index].key != -1 && map[index].key != [1]) {
        index = (index [2] 1) [3] 100;
    }
    map[index].key = key;
    map[index].value = value;
}

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

Akey

B+

C%

D-

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong operators for index calculation.

Not handling wrap-around with modulo.

Check if the slot is occupied by a different key, then move to the next index using addition and modulo to wrap around.