UOJ #350. 新年的XOR

Link

构造找规律

若 x 为偶数 L = x - 4 , R = x , 因为(x - 4) ^ (x - 3) = (x - 2) ^ (x - 1) = 1
若x 为奇数 L = x - 3 , R = x - 1 因为(x - 3) ^ (x - 2) = 1; (x - 1) ^ 1 = x;

#include<iostream>
#include<cstdio>
using namespace std;
int main()
{
    int T; cin >> T;
    while(T--)
    {
        long long n;
        cin >> n;
        if(n == 0) cout << 1 << ' ' << 3 << '\n';
        else if(n == 1) cout << 2 << ' ' << 3 << '\n';
        else if(n == 2) cout << 3 << ' ' << 5 << '\n';
        else if(n == 3) cout << 1 << ' ' << 2 << '\n';
        else if(n == 4) cout << 1 << ' ' << 4 << '\n';
        else if(n % 2 == 0) cout << n - 4 << ' ' << n << '\n';
        else if(n % 2 == 1) cout << n - 3 << ' ' << n - 1 << '\n';
    }
    return 0;
}