ADVANCED DATA STRUCTURES PROGRAM • LEVEL 18 — ADVANCED HASHING

Test Probabilistic Membership with a Bloom Filter

Learn how to test probabilistic membership with a bloom filter using a clear C program.

AdvancedCollision resolutionHash-table design

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

data:Maybe graph:No

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

unsigned int hash1(const char*s){unsigned int h=5381;while(*s)h=h*33u+(unsigned char)*s++;return h;}unsigned int hash2(const char*s){unsigned int h=0;while(*s)h=h*131u+(unsigned char)*s++;return h;}

int main(void)
{
    unsigned int bits=0;const char*words[]={"code","data","tree"};for(int i=0;i<3;i++){bits|=1u<<(hash1(words[i])%32);bits|=1u<<(hash2(words[i])%32);}const char*queries[]={"data","graph"};for(int i=0;i<2;i++){int maybe=(bits&(1u<<(hash1(queries[i])%32)))&&(bits&(1u<<(hash2(queries[i])%32)));printf("%s:%s%c",queries[i],maybe?"Maybe":"No",i==1?'\n':' ');}return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

data:Maybe graph:No

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Set several hashed bit positions; a missing bit proves absence while all set bits mean possible presence.
Display the computed result.

Set several hashed bit positions; a missing bit proves absence while all set bits mean possible presence.

EFFICIENCY

Time and space complexity

Time complexity

O(k) per operation

Auxiliary space

O(bit-array size)

DEBUGGING CHECKLIST

Common mistakes

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Use the correct format specifier for every variable.

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Initialize variables before using their values.

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Check braces, semicolons and input order carefully.

Try it yourself

Practice: Run the program with the sample input, predict its output, and then test one boundary case of your own.