Double Hashing

f(i) = i ? hash2(x)

• Probe sequence is

  • h1(k) mod size
  • (h1(k) + 1 ? h2(x)) mod size
  • (h1(k) + 2 ? h2(x)) mod size
  • …

• Code for finding the next linear probe:

bool findEntry(const Key & k, Entry *& entry) {

int probePoint = hash1(k), hashIncr = hash2(k);

do {

entry = &table[probePoint];

probePoint = (probePoint + hashIncr) % size;

} while (!entry->isEmpty() && entry->key != k);

return !entry->isEmpty();

}

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