94 lines
2.8 KiB
C++
94 lines
2.8 KiB
C++
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#include<bits/stdc++.h>
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using namespace std;
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// Short forms
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#define ll long long
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#define ull unsigned long long
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#define nl '\n'
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#define ff first
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#define ss second
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#define all(x) x.begin(), x.end()
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#define sz(x) (int)(x).size()
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#define pb push_back
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#define mp make_pair
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// Loops
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#define nlp(i, n) for (int i = 0; i < (int)(n); ++i)
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#define lp(i, a, b) for (int i = (int)(a); i <= (int)(b); ++i)
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#define rlp(i, a, b) for (int i = (int)(a); i >= (int)(b); --i)
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#define llp(i,a,b) for (ll i= (ll)(a); i <= (ll)(ll)(b); ++i)
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// STLs
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#define pii pair<int, int>
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#define vi vector<int>
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#define vll vector<ll>
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#define vvi vector<vector<int>>
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#define vvl vector<vector<ll>>
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// Outputs
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#define yes cout<<"YES"<<nl
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#define no cout<<"NO"<<nl
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#define dbg(x) cerr << #x <<" "<< x << endl;
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// Constants
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#define PI 3.141592653589793238
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#define INF LONG_LONG_MAX
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#define MOD 1e9+7
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// Faster Input Output
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#define FAST_IO (ios_base:: sync_with_stdio(false),cin.tie(NULL));
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// Maths
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ll fact(ll n) { if(n==0) return 1; ll res = 1; for (ll i = 2; i <= n; i++) res = res * i; return res; }
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ll nPr(ll n, ll r) { return fact(n) / fact(n - r); }
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ll nCr(ll n, ll r) { return fact(n) / (fact(r) * fact(n - r)); }
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ll gcd(ll a, ll b) { if (b == 0) return a; return gcd(b, a % b); }
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ll lcm(ll a, ll b) { return (a * b) / gcd(a, b);}
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ll mypow(ll a, ll b) { ll ans = 1; while(b){ if (b&1) ans = (ans*a) ; b /= 2; a = (a*a); } return ans; }
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bool isPrime(ll n) { if(n <= 1) return false; for(ll i = 2; i <= sqrt(n); i++) if(n % i == 0) return false; return true; }
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/////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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void solve()
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{
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int l, r;
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cin >> l >> r;
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if ( r < 4)
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cout<< -1 << nl;
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else if(l==r)
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{
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if (isPrime(r))
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cout << -1 << nl;
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else if ( l % 2 == 0 )
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cout << 2 << " " << l-2 << nl;
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else
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{
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for(int i=3; i<=sqrt(r); ++i)
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{
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int j=l-i;
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if(gcd(i,j)!=1)
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{
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cout<<i<<" "<<j<<nl;
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return;
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}
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}
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cout<<-1<<nl;
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}
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}
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else
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{
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if(r%2)
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cout<< 2 << " " << r-3 <<nl;
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else
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cout<< 2 << " "<< r-2 <<nl;
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}
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}
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int main()
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{
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FAST_IO;
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int TC = 1;
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cin >> TC;
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while (TC--) solve();
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}
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