Simple XOR solution codechef
You are given two integers L and R(L+3≤R). Output any four distinctintegers between L and R (inclusive) such that their bitwise XOR is zero.
More formally, output any four integers a1,a2,a3,a4 such that:
- a1⊕a2⊕a3⊕a4=0
- L≤a1,a2,a3,a4≤R
- ai=aj if and only if i=j
If more than one such quadruple exists, you may output any of them. If no such quadruple exists, print −1 instead.
Input Format
Simple XOR solution codechef
- The first line of input will contain a single integer T, the number of test cases. The description of the test cases follows.
- Each test case consists of a single line of input, containing two space-separated integers L,R.
Output Format
For each testcase, output any four distinct integers between L and R such that their bitwise XOR is zero, or output −1 in case no such quadruple of four distinct integers exists.
Constraints
- 1≤T≤1000
- 1≤L,R≤109
- L+3≤R, so there are at least four distinct integers in the range.
Sample Input 1
Simple XOR solution codechef
2
1 4
1 100
Sample Output 1
-1
3 6 9 12
Explanation
Test case 1: There are only four integers in the range and their bitwise XOR is not zero. 1⊕2⊕3⊕4=4
Test case 2: There are many possible answers in this case. One of them is provided above: 3,6,9,12. It can be verified that 3⊕6⊕9⊕12=0.