LeetCode之Single Number

Given an array of integers, every element appears twice except for one. Find that single one.

Note:
Your algorithm should have a linear runtime complexity. Could you implement it without using extra memory?

   

    

     

      

     
     

      

       public static int singleNumber1(int nums[]) {
      
     
    

     

      

     
     

      

       		if (nums == null) 
      
     
    

     

      

     
     

      

       			return 0;
      
     
    

     

      

     
     

      

       		int length = nums.length;
      
     
    

     

      

     
     

      

       		int count = 0;
      
     
    

     

      

     
     

      

       		for (int i = 0; i < length ; i++) {
      
     
    

     

      

     
     

      

        for (int j = 0; j < length; j++) {
      
     
    

     

      

     
     

      

        if (i != j) {
      
     
    

     

      

     
     

      

        if (nums[i] == nums[j]) 
      
     
    

     

      

     
     

      

        continue;
      
     
    

     

      

     
     

      

        else {
      
     
    

     

      

     
     

      

        count++; 
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

        }
      
     
    

     

      

     
     

      

        if (count == length - 1)
      
     
    

     

      

     
     

      

        return nums[i];
      
     
    

     

      

     
     

      

        count = 0;
      
     
    

     

      

     
     

      

        } 
      
     
    

     

      

     
     

      

        return 0;