Majority Number

题目：

Given an array of integers, the majority number is the number that occurs more than half of the size of the array. Find it.

分析：

扔掉俩不一样的数，剩下的数就是主元素

解法：

public int majorityNumber(ArrayList<Integer> nums) {
        // write your code
        int count = 0, ret = -1;
        for(int i = 0; i < nums.size(); i++){
            if(count == 0){
                ret = nums.get(i);
                count = 1;
            }else if(nums.get(i) != ret){
                count--;
            }else{
                count++;
            }
        }
        return ret;
    }