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[leetcode] problem 260 – single number iii

admin 11月 13, 2020 0

Given an array of numbers nums, in which exactly two elements appear only once and all the other elements appear exactly twice. Find the two elements that appear only once.

Example

Input: [1,2,1,3,2,5]

Output: [3,5]

Note

The order of the result is not important. So in the above example, [5, 3] is also correct.
Your algorithm should run in linear runtime complexity. Could you implement it using only constant space complexity?

Code

public int[] singleNumber(int[] nums) {
    int[] result = new int[2];
    int xor = 0;
    int num1 = 0;
    int num2 = 0;

    for (int num : nums)
        xor ^= num;

    int last = xor - (xor & (xor - 1));

    for (int i = 0; i < nums.length; i++) {
        if ((last & nums[i]) == 0)
            num1 ^= nums[i];
        else
            num2 ^= nums[i];
    }

    result[0] = num1;
    result[1] = num2;

    return result;
}