MajorityElement | Topcoder Archive

Problem Statement

An array is said to have a majority element x if strictly more than half of its elements are equal to x (see examples for further clarification).

Given a int[] a, return its majority element, or -1 if it does not have one.

Definition

Class:: MajorityElement
Method:: findMajorityElement
Parameters:: int[]
Returns:: int
Method signature:: int findMajorityElement(int[] a)
(be sure your method is public)

Constraints

a will contain between 1 and 50 elements, inclusive.
Each element of a will be between 0 and 1000, inclusive.

Examples

```
{3, 9, 3, 3, 7}
```
```
Returns: 3
```
Element 3 occurs 3 times, which makes it a majority element of an array with 5 elements.
```
{0, 1000, 984, 0}
```
```
Returns: -1
```
The number of equal elements must be strictly greater than half of array size, so 0 is not a majority element.
```
{5}
```
```
Returns: 5
```
```
{13, 13}
```
```
Returns: 13
```
All elements are equal.
```
{249, 326, 564}
```
```
Returns: -1
```
All elements are distinct, so there is no majority element.

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