Boyer-Moore-Voting

#include <iostream>
#include <vector>

using namespace std;

int boyer_moore_voting_algorithm(vector<int>& nums) {
    int n = nums.size();

    // Step 1: Find the majority candidate
    int candidate = nums[0];
    int count = 1;
    for (int i = 1; i < n; i++) {
        if (nums[i] == candidate) {
            count += 1;
        } else if (count == 0) {
            candidate = nums[i];
            count = 1;
        } else {
            count -= 1;
        }
    }

    // Step 2: Verify the majority candidate
    count = 0;
    for (int i = 0; i < n; i++) {
        if (nums[i] == candidate) {
            count += 1;
        }
    }

    if (count > n/2) {
        return candidate;
    } else {
        return -1;
    }
}

int main() {
    vector<int> nums = {2, 2, 1, 1, 1, 2, 2};
    int majority = boyer_moore_voting_algorithm(nums);
    if (majority != -1) {
        cout << "Majority element: " << majority << endl;
    } else {
        cout << "No majority element found." << endl;
    }
    return 0;
}