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 };

    

Majority Element II

原文：http://www.cnblogs.com/zl1991/p/4670117.html