# Majority Element | Set-2 (Hashing)

Given an array of size N, find the majority element. The majority element is the element that appears more than times in the given array.

**Examples:**

Input: [3, 2, 3] Output: 3 Input: [2, 2, 1, 1, 1, 2, 2] Output: 2

The problem has been solved using 4 different methods in the previous post. In this post hashing based solution is implemented. We count occurrences of all elements. And if count of any element becomes more than n/2, we return it.

Hence if there is a majority-element, it will be the value of the key.

Below is the implementation of the above approach:

## C++

`#include<bits/stdc++.h> ` `using` `namespace` `std; ` ` ` `#define ll long long int ` ` ` `// function to print the majority Number ` `int` `majorityNumber(` `int` `arr[], ` `int` `n) ` `{ ` ` ` `int` `ans = -1; ` ` ` `unordered_map<` `int` `, ` `int` `>freq; ` ` ` `for` `(` `int` `i = 0; i < n; i++) ` ` ` `{ ` ` ` `freq[arr[i]]++; ` ` ` `if` `(freq[arr[i]] > n / 2) ` ` ` `ans = arr[i]; ` ` ` `} ` ` ` `return` `ans; ` `} ` ` ` `// Driver code ` `int` `main() ` `{ ` ` ` `int` `a[] = {2, 2, 1, 1, 1, 2, 2}; ` ` ` `int` `n = ` `sizeof` `(a) / ` `sizeof` `(` `int` `); ` ` ` `cout << majorityNumber(a, n); ` ` ` `return` `0; ` `} ` ` ` `// This code is contributed ` `// by sahishelangia ` |

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## Python

`# function to print the ` `# majorityNumber ` `def` `majorityNumber(nums): ` ` ` ` ` `# stores the key count ` ` ` `key, count ` `=` `None` `, ` `0` ` ` ` ` `# iterate in the array ` ` ` `for` `num ` `in` `nums: ` ` ` ` ` `# key is 0 ` ` ` `if` `key ` `is` `None` `: ` ` ` `key, count ` `=` `num, ` `1` ` ` `else` `: ` ` ` `if` `key ` `=` `=` `num: ` ` ` `count ` `+` `=` `1` ` ` `else` `: ` ` ` `count ` `-` `=` `1` ` ` ` ` `if` `count ` `=` `=` `0` `: ` ` ` `key ` `=` `None` ` ` ` ` `return` `key ` ` ` `# Driver Code ` `a ` `=` `[` `2` `, ` `2` `, ` `1` `, ` `1` `, ` `1` `, ` `2` `, ` `2` `] ` `print` `majorityNumber(a) ` |

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**Output:**

2

Below is the time and space complexity of the above algorithm:-

**Time Complexity** : O(n)

**Auxiliary Space** : O(n)

## Recommended Posts:

- Majority Element
- Count majority element in a matrix
- Majority element in a linked list
- Check if an array has a majority element
- Majority element in a circular array of 0's and 1's
- Check for Majority Element in a sorted array
- Double Hashing
- Coalesced hashing
- Applications of Hashing
- Hashing | Set 1 (Introduction)
- Hashing in Java
- Hashing | Set 2 (Separate Chaining)
- Hashing | Set 3 (Open Addressing)
- C++ program for hashing with chaining
- Practice Problems on Hashing

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