/// <summary>
/// Finds Majority element in the given array using Boyer Moore Voting algorithm.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="a">array</param>
/// <returns>
/// Majority element
/// </returns>
public static MajorityElementResult <T> FindMajorityElementByBoyerMooreAlgorithm <T>(T[] a)
{
MajorityElementResult <T> result = new MajorityElementResult <T>();
if (a.Length > 0)
{
result.Count = 1;
result.MajorityElement = a[0];
}
for (int i = 1; i < a.Length; i++)
{
if (a[i] == null)
{
continue;
}
if (a[i].Equals(result.MajorityElement))
{
result.Count++;
}
else
{
result.Count--;
}
if (result.Count == 0)
{
result.MajorityElement = a[i];
result.Count = 1;
}
}
if (result.Count > 0)
{
result.Count = 0;
for (int i = 0; i < a.Length; i++)
{
if (a[i] == null)
{
continue;
}
if (a[i].Equals(result.MajorityElement))
{
result.Count++;
}
}
if (result.Count > Math.Floor(a.Length / 2.0))
{
return(result);
}
}
return(null);
}
/// <summary>
/// Finds Majority element in the given array using brute force method.
/// </summary>
/// <typeparam name="T"></typeparam>
/// <param name="a">array</param>
/// <returns>
/// Majority element
/// </returns>
public static MajorityElementResult <T> FindMajorityElementByBruteForceMethod <T>(T[] a)
{
MajorityElementResult <T> result = new MajorityElementResult <T>();
for (int i = 0; i < a.Length; i++)
{
if (a[i] == null)
{
continue;
}
var tempCount = 0;
for (int j = i; j < a.Length; j++)
{
if (a[j] == null)
{
continue;
}
if (a[i].Equals(a[j]))
{
tempCount++;
}
}
if (tempCount > result.Count)
{
result.Count = tempCount;
result.MajorityElement = a[i];
}
}
if (result.Count > Math.Floor(a.Length / 2.0))
{
return(result);
}
return(null);
}
