# LeetCode: 169. Majority Element

**The Problem**

Given an array `nums`

of size `n`

, return *the majority element*.

The majority element is the element that appears more than `⌊n / 2⌋`

times. You may assume that the majority element always exists in the array.

**Example**

```
Example 1:
Input: nums = [3,2,3]
Output: 3
Example 2:
Input: nums = [2,2,1,1,1,2,2]
Output: 2
```

**Constraints:**

`n == nums.length`

`1 <= n <= 5 * 10`

^{4}`-10`

^{9}<= nums[i] <= 10^{9}

**The Solution**

We opted for a simple approach using a **for** loop

```
int majorityElement(vector<int>& nums) {
unordered_map<int, int> count;
int n = ceil(nums.size() / 2.0);
for(int i = 0; i < nums.size(); ++i) {
++count[nums[i]];
if(count[nums[i]] >= n) return nums[i];
}
return -1;
}
```

🧠

Github with all the solution including test cases.

Let's break down the code step by step:

`int majorityElement(vector<int>& nums) {`

: This line defines a function named`majorityElement`

that takes a reference to a vector of integers (`nums`

) as its parameter. The function returns an integer.`unordered_map<int, int> count;`

: Here, an unordered map named`count`

is declared. This map will store the count of occurrences of each integer in the input vector.`int n = ceil(nums.size() / 2.0);`

: This line calculates the minimum threshold count required for an element to be considered a majority element. It is computed as half the size of the input vector, rounded up to the nearest integer.`for(int i = 0; i < nums.size(); ++i) {`

: This line starts a loop that iterates over each element of the input vector.`++count[nums[i]];`

: Inside the loop, the code increments the count of the current element (`nums[i]`

) in the`count`

map.`if(count[nums[i]] >= n) return nums[i];`

: This condition checks if the count of the current element has reached or exceeded the minimum threshold required for it to be considered a majority element. If so, the function immediately returns the current element as the majority element.`return -1;`

: If the loop completes without finding a majority element, the function returns`-1`

, indicating that there is no majority element in the input vector.