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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。

Majority Element(ARRAY-BINARY SEARCH)