Given a non-empty 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?
Example 1:
Input: [2,2,1]
Output: 1
Example 2:
Input: [4,1,2,1,2]
Output: 4
we use bitwise XOR to solve this problem :
first , we have to know the bitwise XOR in java
0 ^ N = N
N ^ N = 0
So..... if N is the single number
N1 ^ N1 ^ N2 ^ N2 ^..............^ Nx ^ Nx ^ N
= (N1^N1) ^ (N2^N2) ^..............^ (Nx^Nx) ^ N
= 0 ^ 0 ^ ..........^ 0 ^ N
= N
class Solution {
public int singleNumber(int[] nums) {
int ans = 0;
for (int i = 0; i < nums.length; i++) {
ans ^= nums[i];
}
return ans;
}
}