DATA STRUCTURES PROGRAM • ARRAY TECHNIQUES

Find a Majority Element with Boyer-Moore Voting

Learn how to find a majority element with boyer-moore voting using a clear C program.

IntermediateBoyer-MooreCandidateVerification

PROBLEM UNDERSTANDING

Input and expected output

Sample input

No input required

Sample output

Majority = 2

COMPLETE C PROGRAM

Complete C implementation

#include <stdio.h>

int main(void)
{
    int values[] = {2, 2, 1, 1, 1, 2, 2};
    int candidate = 0, votes = 0;
    for (int index = 0; index < 7; index++) {
        if (votes == 0) candidate = values[index];
        votes += values[index] == candidate ? 1 : -1;
    }
    int frequency = 0;
    for (int index = 0; index < 7; index++) if (values[index] == candidate) frequency++;
    if (frequency > 7 / 2) printf("Majority = %d\n", candidate);
    else puts("No majority element.");
    return 0;
}

CURRENT STEP

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SELECTED LINE

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EXPECTED OUTPUT FOR THE SAMPLE

Majority = 2

0%Step 0 of 0

PROGRAM EXPLANATION

Algorithm and explanation

Read the required input values.
Cancel different values, then verify that the surviving candidate occurs more than half the time.
Display the computed result.

Cancel different values, then verify that the surviving candidate occurs more than half the time.

EFFICIENCY

Time and space complexity

Time complexity

O(n)

Auxiliary space

O(1)

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.

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.