递归+pair

https://codeforces.com/contest/2053/problem/C

#include<bits/stdc++.h>
#define lc p<<1
#define rc p<<1|1
#define INF 2e9
using namespace std;

#define endl '\n'
using ll = long long;
using pii = pair<ll, int>;
const double PI = acos(-1);
const int N = 2e5 + 10;
const int mod = 1e9 + 7;
int k;
ll sum;
pii fun(int l,int r){
	ll t=(r-l+1);
	if(t>=k){
		ll mid=(l+r)>>1;
		if(t%2){
			
			auto [sum,cnt]=fun(l,mid-1);
			return {sum*2+cnt*mid+mid,2*cnt+1};
			
		}
		else {
			auto [sum,cnt]=fun(l,mid);
			return {sum*2+cnt*mid,2*cnt};
		}
	}
	return {0,0};
}
void solve() {
	int n;cin>>n>>k;
	cout<<fun(1,n).first<<endl;
}

int main() {
	ios::sync_with_stdio(false);
	cin.tie(nullptr), cout.tie(nullptr);
	
	int T = 1;
	cin>>T;
	while (T--) {
		solve();
	}
	
	return 0;
}