DSA · Theory

Hashing and its Applications

Theory

559/810

Isha only reaches for Hashing and its Applications when name → phone has to stay correct in a diary.

Hashing and its Applications order: meaning → key % size + collision plan → one limit. Dumping ten features helps nobody.

Without Hashing and its Applications, a diary gets messy and name → phone is hard to trust.

Use Hashing and its Applications when name → phone must stay clear. If a simpler DSA step works, use that instead.

If name → phone breaks under Hashing and its Applications, check bad hash → pile-up first.

After Hashing and its Applications, Isha should still remember bad hash → pile-up.

Viva for Hashing and its Applications — what it is → key % size + collision plan → the mistake (bad hash → pile-up).

Exam tip

Board: name → phone. Dry-run Hashing and its Applications. Name the trap: bad hash → pile-up.

freq = {}
for ch in "banana":
    freq[ch] = freq.get(ch, 0) + 1
print(freq)
print(freq.get("a"), freq.get("z", 0))

Hashing and its Applications — hash maps give average O(1) insert/lookup — dict in Python.