169. Majority Element

Given an array of size n, find the majority element. The majority element is the element that appears more than ⌊ n/2 ⌋ times.

You may assume that the array is non-empty and the majority element always exist in the array.

摩尔投票法：http://mabusyao.iteye.com/blog/2223195
这种投票法先将第一个数字假设为众数，然后把计数器设为1，比较下一个数和此数是否相等，若相等则计数器加一，反之减一。然后看此时计数器的值，若为零，则将当前值设为候选众数。以此类推直到遍历完整个数组，当前候选众数即为该数组的众数。代码如下

class Solution {public:    int majorityElement(vector<int>& nums) {        int nowNum = nums[0];        int count = 1;        for(int i = 1; i < nums.size() ; i ++){            if(count == 0){                nowNum = nums[i];                count = 1;            }else{                if(nums[i] == nowNum){                    count ++;                }else{                    count --;                }            }        }        return nowNum;    }};