【链接】 我是链接,点我呀:)
【题意】

让你求出l~r当中二进制表示1的个数最多的数x

【题解】

最多有64位
我们可以从l开始一直增大到r
怎么增大?
找到l的二进制表示当中0所在的位置
假设i这一位的0经过加法变成了1
那么我们再从低位到高位依次枚举那一位为1就好
然后把这个二进制转换成十进制
看看它是不是比ri来的小
如果是,则尝试更新最小值
a[i]=(int)一个long类型的数字%2
a[i]是Int
会出错..

【代码】

import java.io.*;
import java.util.*;

public class Main {
    
    
    static InputReader in;
    static PrintWriter out;
        
    public static void main(String[] args) throws IOException{
        //InputStream ins = new FileInputStream("E:\\rush.txt");
        InputStream ins = System.in;
        in = new InputReader(ins);
        out = new PrintWriter(System.out);
        //code start from here
        new Task().solve(in, out);
        out.close();
    }
    
    static int N = 50000;
    static class Task{
        int n,len;
        long li,ri;
        long Bits[];
        
        public void solve(InputReader in,PrintWriter out) {
            Bits = new long[100];
            n = in.nextInt();
            for (int ii = 1;ii <= n;ii++) {
                li = in.nextLong();ri = in.nextLong();
                long ans = li;int ans1 = 0;
                for (int j = 63;j >= 1;j--){
                    Bits[j] = li%2;
                    li = li/2;
                    ans1 += Bits[j];
                }
                
                //out.println("ans="+ans);
                //out.println("ans1="+ans);
                long temp = ans;
                int temp1 = ans1;
                long now = 1;
                for (int j = 63;j >= 1;j--) {
                    temp = temp - now*Bits[j];
                    temp1-=Bits[j];
                    if(Bits[j]==0) {
                        temp1 = temp1+1;
                        temp = temp + now;
                        //out.println("temp="+temp+" now = "+now);
                        if (temp<=ri) {
                            if (temp1>ans1) {
                                ans1 = temp1;
                                ans = temp;
                            }else if (temp1==ans1 && temp<ans) {
                                ans = temp;
                            }
                        }
                        long temp2 = 1,cur = 0;
                        for (int k = 1;k <= (63-j);k++) {
                            cur = cur + temp2;
                            if (temp + cur<=ri) {
                                if (temp1 + k > ans1) {
                                    ans1 = temp1 + k;
                                    ans = temp + cur;
                                }else if (temp1+k==ans1 && temp+cur<ans) {
                                    ans = temp + cur;
                                }
                            }else break;
                            temp2 = temp2*2;
                        }
                        temp = temp - now;
                        temp1 = temp1-1;
                    }
                    now = now * 2;
                }
                out.println(ans);
                //out.println(ans1);
            }
            
        }
    }

    

    static class InputReader{
        public BufferedReader br;
        public StringTokenizer tokenizer;
        
        public InputReader(InputStream ins) {
            br = new BufferedReader(new InputStreamReader(ins));
            tokenizer = null;
        }
        
        public String next(){
            while (tokenizer==null || !tokenizer.hasMoreTokens()) {
                try {
                tokenizer = new StringTokenizer(br.readLine());
                }catch(IOException e) {
                    throw new RuntimeException(e);
                }
            }
            return tokenizer.nextToken();
        }
        
        public int nextInt() {
            return Integer.parseInt(next());
        }
        
        public long nextLong() {
            return Long.parseLong(next());
        }
    }
}