Sword refers to the number of occurrences of the number in the Offer-58 array

public int[] singleNumbers(int[] nums) { 
    int x = 0, y = 0, n = 0, m = 1; 
    // Traverse XOR 
    for(int num: nums) { 
        n ^= num; 
    } 
    // Shift left in a loop, calculate m 
    while((n & m) == 0) { 
        m <<= 1; 
    } 
    // Traverse nums grouping 
    for(int num: nums) { 
        if((num & m) != 0) { 
            x ^= num; 
        } else { 
            y ^= num; 
        } 
    } 
    return new int[] {x, y}; 
}