169. Majority Element

class Solution {
    public int majorityElement(int[] nums) {
        int majorityElement = 0, votes = 0;
        for (int num : nums) {
            if (votes == 0) {
                majorityElement = num;
            }

            votes += num == majorityElement ? 1 : -1;
        }

        return majorityElement;
    }
}

Reference

169. Majority Element
剑指 Offer 39. 数组中出现次数超过一半的数字
面试题 17.10. 主要元素