ADVANCED DATA STRUCTURES PROGRAM • LEVEL 18 — ADVANCED HASHING

Resolve Collisions with Double Hashing

Learn how to resolve collisions with double hashing using a clear C program.

AdvancedCollision resolutionHash-table design

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

2:41 5:18 9:22 10:44

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int table[13];for(int i=0;i<13;i++)table[i]=-1;int keys[]={18,41,22,44};
    for(int k=0;k<4;k++){int h1=keys[k]%13,h2=7-keys[k]%7;for(int step=0;step<13;step++){int slot=(h1+step*h2)%13;if(table[slot]<0){table[slot]=keys[k];break;}}}
    for(int i=0;i<13;i++){if(table[i]>=0)printf("%d:%d ",i,table[i]);}
    putchar('\n');return 0;
}

CURRENT STEP

Select Start to walk through the important lines.

SELECTED LINE

No line selected

EXPECTED OUTPUT FOR THE SAMPLE

2:41 5:18 9:22 10:44

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Use a second hash as the probe step so colliding keys follow different sequences.
Display the computed result.

Use a second hash as the probe step so colliding keys follow different sequences.

EFFICIENCY

Time and space complexity

Time complexity

Average O(1), worst O(n)

Auxiliary space

O(table size)

DEBUGGING CHECKLIST

Common mistakes

Check this

Use the correct format specifier for every variable.

Check this

Initialize variables before using their values.

Check this

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.