buptoj 1578

题目链接：http://acm.bupt.edu.cn/onlinejudge/newoj/showProblem/show_problem.php?problem_id=1578

#include <cstdio>
#include <cmath>
#include <algorithm>
#include <iostream>
#include <cstring>
#include <queue>
#include <vector>
#include <bitset>

using namespace std;
int a,b;
int calculatenum(int num){
    int ans = 0;
    while(num>0){
        num = num/2; 
        ans++;
    }
    return ans;
}
int calculateone(int num){
    int ans = 0;
    while(num>0){
        if(num%2)   ans++;
        num = num/2;
    }
    return ans;
}

int main(){
//    if(freopen("input.txt","r",stdin)== NULL)  {printf("Error\n"); exit(0);}

    int T;
    cin>>T;
    while(T--){
        
        cin>>a>>b;
        
        int numa = calculatenum(a); 
        int numb = calculatenum(b);   
         
        if(a == b){
            printf("%d\n",calculateone(b));
        }
        else if(b == (1<<numb )- 1){
            printf("%d\n",numb);
        }  
        else if(numa < numb) {
            printf("%d\n",numb-1);
        }
        else{ 
           int maxnum = calculateone(b); 
           int temp = b;
            numa--;
           while(a>>numa == b>>numa){
                  temp = temp%(1<<numa); 
                  numa--; 
              }  
              numa++;  
              if(temp != (1<<numa)-1){  
                    maxnum = calculateone(b / (1<<numa))  + calculatenum(temp) - 1;
              }
                 printf("%d\n",maxnum);
        }
    
    }
}