Majority Element II

Given an integer array of size n, find all elements that appear more than ⌊ n/3 ⌋ times. The algorithm should run in linear time and in O(1) space.

Hint:

  1. How many majority elements could it possibly have?
  2. Do you have a better hint? Suggest it! 
     1 class Solution {
 2 public:
 3     vector<int> majorityElement(vector<int>& nums) {
 4         int i;
 5         int count1,count2;
 6         int num1,num2;
 7         int n=nums.size();
 8         vector<int> res;
 9         count1=0;
10         count2=0;
11         for(i=0;i<n;i++){
12             if(count1==0 || num1==nums[i]){
13                 num1=nums[i];
14                 count1++;
15             }
16             else if(count2==0 || num2==nums[i]){
17                     num2=nums[i];
18                     count2++;
19                 }
20             else
21             {
22                 count1--;
23                 count2--;
24             }
25         }
26         count1=0;
27         count2=0;
28         for(i=0;i<n;i++)
29         {
30             if(num1==nums[i])
31               count1++;
32             else if(num2==nums[i])
33               count2++;
34             
35         }
36         if(count1>n/3)
37           res.push_back(num1);
38         if(count2>n/3)
39           res.push_back(num2);
40           return res;
41     }
42 };

     

posted @ 2015-07-23 12:29  鸭子船长  阅读(196)  评论(0)  编辑  收藏  举报