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BoyerMoore.java
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49 lines (45 loc) · 1.33 KB
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/* this Code is the illustration of Boyer moore's voting algorithm to
find the majority element is an array that appears more than n/2 times in an array
where "n" is the length of the array.
For more information on the algorithm refer
https://en.wikipedia.org/wiki/Boyer%E2%80%93Moore_majority_vote_algorithm
*/
package com.thealgorithms.others;
import java.util.*;
public class BoyerMoore {
public static int findmajor(int[] a) {
int count = 0;
int cand = -1;
for (int i = 0; i < a.length; i++) {
if (count == 0) {
cand = a[i];
count = 1;
} else {
if (a[i] == cand) {
count++;
} else {
count--;
}
}
}
for (int i = 0; i < a.length; i++) {
if (a[i] == cand) {
count++;
}
}
if (count > (a.length / 2)) {
return cand;
}
return -1;
}
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
int n = input.nextInt();
int[] a = new int[n];
for (int i = 0; i < n; i++) {
a[i] = input.nextInt();
}
System.out.println("the majority element is " + findmajor(a));
input.close();
}
}