题解

用递归就彳亍

#include<bits/stdc++.h>
using namespace std;
#define ll long long

struct info{
	ll num, sum;
};

info f(int n, int p){
	if (n == 0) return {1 - p, 0};
	ll t = 1, s;
	while (t <= n){
		s = t;
		t *= 2;
	}
	ll y = s - 1, n1, s1;
	if (y == 0){
		n1 = 1 - p;
		s1 = 0;
	}else if (y == 1){
		n1 = 1;
		s1 = (p == 1);
	}else{
		n1 = (y + 1) / 2;
		s1 = y * (y + 1) / 4;
	}
	info a = f(n - s, 1 - p);
	n1 += a.num;
	s1 += s * a.num + a.sum;
	return {n1, s1};
}

ll l, r;
int main(){
	cin >> l >> r;
	cout << f(r, 1).sum - f(l - 1, 1).sum;
	return 0;
}