Majority Element(ARRAY-BINARY SEARCH)

QUESTION

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.

FIRST TRY

每找出两个不同的element，则成对删除。最终剩下的一定就是所求的。

class Solution {
public:
    int majorityElement(vector<int> &num) {
        int ret;
        int nTimes = 0;
        for(int i = 0; i < num.size(); i++){
            if(nTimes == 0) 
            {
                ret = num[i];
                nTimes++;
            }
            else if(ret == num[i]) nTimes++;
            else nTimes--; //2 different number, delete
        }
        return ret;
    }
};

Result: Accepted

可扩展到⌊ n/k ⌋的情况，每k个不同的element进行成对删除。